Category: Uncategorized

The North Atlantic right whale (NARW) has been officially recognized as an endangered species according to the Endangered Species Act since 1970 (NOAA Fisheries, 2024). With only 360 individuals remaining, 70 of which are reproductively active females, understanding their past and current challenges is crucial for a more hopeful future.

Baleen whales were commercially hunted from the 16^th to 19^th century for their valuable blubber and baleen plates. During the peak of whaling, it was quickly realized that the North Atlantic species not only possessed the thickest layer of blubber but also remained floating at the surface after being harpooned. These characteristics earned them the name right whale, as they were the “right whale” to hunt, and thus made them a primary target. By the 19^th century, their numbers had decreased to the point where they no longer played a significant role in the whaling industry. The International Whaling Commission acknowledged that NARWs were on the brink of extinction and committed to globally protect the species in 1946 (Greene & Pershing, 2004). However, despite decades of protection, why has the population failed to recover?

With the end of commercial whaling, there was hope that the population of the NARW would gradually recover however, the reproduction rate is unable to keep up with the rate of mortalities. In addition to vessel strikes and fishing gear entanglement being the primary causes of death, the inevitable crisis of climate change has also been discovered to be a major contributing factor.

Through previous years of tracking NARW migration patterns, scientists revealed that right whales travelled annually to the Bay of Fundy. The Bay holds great significance for this species, particularly due to its abundance of copepod plankton, which are known as the primary food source for the NARWs.

Now, with the Bay of Fundy being the fastest-warming ocean region across the globe, copepods are adapting in ways that are proving to be detrimental to the right whales (Bucci, Thomas, & Cetinić, 2020). A recent study confirmed this correlation by examining the size and lipid content of copepod populations. The study found that warmer water temperatures are negatively associated with copepod size, resulting in reduced energy intake (lipid) for North Atlantic right whales (Helenius et al., 2023). As a result, these whales are not only shortening their migration route to preserve their energy, but also fail to meet the energetic requirements needed to reproduce. If mom isn’t eating a substantially nutritious diet, is she really going to want to grow and birth a 2,000 lbs calf? I know I wouldn’t!

NARWs are therefore changing their migration trajectory in hopes of finding higher-quality food as temperatures are increasing. Previously, along the Western Atlantic coast, shipping lanes were diverged and speed limits were enforced during the seasons when right whales were likely to be present. But now that groups are travelling to colder waters with higher prey quality, these regions have yet to catch up and enforce these lifesaving regulations (NOAA Fisheries, 2024).

This discovery allows scientists to track and predict NARW populations based on prey quality and water temperatures. By doing so, it can hopefully limit the amount of vessel strikes and fishing gear entanglement by laying out regulations sooner rather than later. The earlier we can detect these changes, the closer we are to saving the right whale species. As a community, our job is to continue to educate and spread awareness on these occurring topics so that they will not only have a past but will be given a chance for a brighter future!

Written by:  Gaby Caird

References:

1. NOAA Fisheries. (2024). North Atlantic right whale. Retrieved June 4, 2024, from https://www.fisheries.noaa.gov/species/north-atlantic-right-whale
2. Greene, C.H., & Pershing, A.J. (2004). Climate and the conservation biology of North Atlantic right whales: the right whale at the wrong time? Ecology, 5(2), 29-45. https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/1540-9295%282004%29002%5B0029%3ACATCBO%5D2.0.CO%3B2
3. Bucci, A. F., Thomas, A. C., & Cetinić, I. (2020). Interannual variability in the thermal habitat of Alexandrium catenella in the Bay of Fundy and the implications of climate change. Frontiers in Marine Science, 7, Article 587990. https://www.frontiersin.org/articles/10.3389/fmars.2020.587990/full

4. Helenius, L. K., Head, E. J. H., Jekielek, P., Orphanides, C. D., Pepin, P., Perrin, G., Plourde, S., Ringuette, M., Runge, J. A., Walsh, H. J., & Johnson, C. L. (2023). Spatial variability in size and lipid content of the marine copepod Calanus finmarchicusacross the Northwest Atlantic continental shelves: implications for North Atlantic right whale prey quality. Journal of plankton research, 46(1), 25–40. https://doi.org/10.1093/plankt/fbad047
5. Knowlton, A. R., Hamilton, P. K., Marx, M. K., Pettis, H. M., & Kraus, S. D. (2012). Monitoring North Atlantic right whale Eubalaena glacialis entanglement rates: a 30 yr retrospective. Marine Ecology Progress Series, 466, 293–302. http://www.jstor.org/stable/24876125

What is the first think you think of when you hear the word “shark”?

Is it a bloodthirsty man eater? A huge underwater torpedo with thrashing jaws and sharp teeth? Or is it perhaps the iconic Jaws theme song? Many people who hear the word “shark” immediately think of the horrors portrayed through movies and tv shows regarding these insatiable eating machines. But what if I were to tell you they aren’t exactly correct? In regard to some species at least, these allegations couldn’t be farther from the truth, and instead can be rather detrimental to these species’ reputations.

One such species I am referring to here is the elusive basking shark. This species, despite its name, is actually a fish. And while all sharks do in fact fall under the fish category not all fish fall into the shark category. To be a shark one must have a number of characteristics which distinguishes them from other fish. One such characteristic consists of having a skeleton made out of cartilage rather than one made of bone.

Out of all the fish in the ocean the basking shark is considered to be the second largest fish species in the world, following close behind the magnificent whale shark. These species grow up to maximum lengths of 12 meters (40 feet), and 18 meters (60 feet) respectively, and surprisingly enough these species do not rely on eating other fish to reach these massive lengths.

But if they don’t rely on eating fish to grow this big, they must be eating something much bigger than fish, right?

(Gill Rakers)

(Baleen Plate)

WRONG! This species is actually a filter-feeder who relies on plankton (small and microscopic organisms who float/drift with the current) as its main food source, much like the baleen whales commonly found throughout the Bay of Fundy. However, dissimilarly to baleen whales, these basking sharks do not have baleen plates, rather they have massive gill slits that extend almost completely around  their heads which are lined with gill rakers. These gill rakers are bristle-like and grow to about 10cm in length, with each gill slit carrying between 1000-1300 rakers along each arch. Also referred to as planktivores, basking sharks actively select foraging areas with high densities of plankton, containing both phytoplankton (plants) and zooplankton (tiny animals). When feeding the basking shark will reduce its speed by approximately 24% and its gills and mouth expand massively, filtering approximately two thousand tons of sea water every hour!

But why slow down to eat? Wouldn’t they catch more food if they swam faster? The answer to that is somewhat complicated. While they would in theory catch more prey at higher speeds, they also risk expending very high amounts of energy. Basking sharks require a perfect balance. Swim too slow and they may not filter enough food to fulfil their metabolic needs, or swim too fast and risk wasting more energy than they gain from the prey they catch. This perfectly balanced speed is called optimal foraging speed, where they maximize food ingested with the lowest energetic cost.

But one question still remains. How do they grow so big by eating such small prey?

Let’s break it down into simple terms. In this scenario phytoplankton will contain 1000 units of energy. When the phytoplankton is eaten by zooplankton it loses some energy, so the zooplankton only gains 100 units of energy. The zooplankton is then eaten by a small fish who only gains 10 units of energy, and the predator who eats the fish only gains 1 unit of energy. This trend then continues on until it reaches the top carnivores.

So, in other words, the closer you eat to the bottom of the food chain the higher amounts of energy you will gain. This is why the basking shark is able to grow to such large lengths. Because they feed on phytoplankton and zooplankton, they are able to fulfil their metabolic needs and then, using the abundance of extra energy they have, they are then able to direct it towards other areas such as their growth.

Written by Jayde Rapp

References

Campana, S. E., Shelton, P. A., Simpson, M., & Lawson, J. (2008). Status of basking sharks in Atlantic     Canada. Fisheries and Oceans.

How do whale and basking sharks grow so big eating such small food?. Wildlife Online. (n.d.).             https://www.wildlifeonline.me.uk/questions/answer/how-do-whale-and-basking-sharks-   grow-so-big-eating-such-small-food

Matthews, L. H., & Parker, H. W. (1950, November). Notes on the anatomy and biology of the Basking      Shark (Cetorhinus maximus (Gunner)). In Proceedings of the Zoological Society of London (Vol. 120, No. 3, pp. 535-576). Oxford, UK: Blackwell Publishing Ltd.

Sims, D. W. (2000). Filter-feeding and cruising swimming speeds of basking sharks compared with  optimal models: they filter-feed slower than predicted for their size. Journal of Experimental     Marine Biology and Ecology, 249(1), 65-76.

Sims, D. W., & Quayle, V. A. (1998). Selective foraging behaviour of basking sharks on zooplankton in a   small-scale front. Nature, 393(6684), 460-464.

By: Madison Malloy

Ocean acidification is the process of the ocean becoming more acidic (as the name implies), and is caused by an increase in CO2 (carbon dioxide) in the atmosphere and ocean. CO2 concentration has been on the rise in the atmosphere for the past 200 years as we progressively began to emit more greenhouse gases (National Oceanic and Atmospheric Administration [NOAA], 2012). A large increase in CO2 in the atmosphere can not only have a warming effect in the atmosphere, but in turn can also allow more carbon dioxide to be absorbed into the ocean. It is estimated that around one-third of the CO2 produced in the atmosphere is absorbed by the ocean (IAEA 2022). When too much is absorbed, it can have adverse impacts on organisms, as well as on how the ocean functions as a whole.

Many organisms rely on calcium carbonate to build their shells (IAEA, 2022)

When CO2 is absorbed, a series of reactions take place that result in fewer carbonate ions in the ocean. Carbonate ions are pretty cool to have around, as they help to make up protective parts of many important organisms in the ocean, including shellfish, coral, and Echinoderms. When there is more CO2 is being absorbed and less carbonate in the ocean, the calcifiers (organisms that use calcium carbonate to build parts of their bodies) have less stuff available to use. This can be harmful to them, the ocean, and people, as they play a vital role in ecosystems and the livelihoods of coastal communities.

Fishing boats on the Bay of Fundy (Saltscapes Magazine, n.d.)

Ocean acidification can have a large impact on people that rely on the ocean. It has been estimated that 3 billion people worldwide have livelihoods that depend on the ocean, and we must also take into account the cultural traditions that have depended on the ocean for generations (IAEA, 2022).

Sea stars on the sea floor (Journal of Young Investigators, 2017)

One group of organisms that may be greatly impacted by ocean acidification are Echinoderms, which include sea stars and sea urchins. Here in St. Andrews, you can find sea stars and sea urchins hanging out at the wharf and in the intertidal zone every day! Sea stars and sea urchins need calcium carbonate to make up various parts, and with less available carbonate in the ocean, they may be more vulnerable to predators, as well as have a harder time feeding and moving (Seattle Aquarium, n.d.). Negative impacts on shellfish can also be observed, with the acidic seawater capable of deteriorating the shells of the young of some species before they can fully form (NOAA, n.d.). This can present challenges for the livelihoods and diets of coastal Indigenous communities that rely on shellfish and other calcifiers as a large portion of their diet (UW News, n.d.)

Purple sea urchins (Jeremy Glass, 2017)

Despite how grim it may seem, there are efforts happening locally and internationally to address the issues of ocean acidification and climate change. As a method to track the changing ocean conditions, Indigenous-led monitoring and management is essential to understanding the impacts on ecosystems and coastal communities (Oceans North, n.d.). Various studies are also underway to explore ways that organisms are adapting, as well as information that can inform policy changes on a larger scale.

A recent study suggests that protecting important habitats like mangroves and seagrass can improve the alkalinity of the surrounding water on a local scale by absorbing more CO2 out of the atmosphere (Nature News, 2023). A different study found that a calcareous sponge, Paraleucilla magna, was able to make its skeleton under very acidic conditions, which may be promising for its ability to adapt should acidification progress (Nature News, 2023). Although these are only a few examples, there are countless studies that have been completed or are underway that aim to learn more about the impacts of this issue. In the face of climate change and ocean acidification, solutions that involve and value the knowledge of coastal communities and Indigenous communities are essential in addition to knowledge derived from scientific research.

References

Fakhraee, M., Planavsky, N. J., & Reinhard, C. T. (2023, May 29). Ocean alkalinity enhancement through restoration of Blue Carbon Ecosystems. Nature News. https://www.nature.com/articles/s41893-023-01128-2

Glass, J. (2019, October 18). Sea urchins are the edible pincushions of the Ocean. HowStuffWorks. https://animals.howstuffworks.com/marine-life/sea-urchin.htm

Hawkins, C. N., & Pain, C. S. (n.d.). Oceans and climate. Oceans North. https://www.oceansnorth.org/en/what-we-do/oceans-and-climate/

IAEA. (2022, December 15). How carbon emissions acidify our ocean. IAEA. https://www.iaea.org/bulletin/how-carbon-emissions-acidify-our-ocean

NOAA. (n.d.) Ocean Acidification’s impact on oysters and other shellfish. https://www.pmel.noaa.gov/co2/story/Ocean+Acidification%27s+impact+on+oysters+and+other+shellfish

Ocean acidification and sea urchins. Seattle Aquarium. (n.d.). https://www.seattleaquarium.org/blog/ocean-acidification-and-sea-urchins#:~:text=Ocean%20acidification%20could%20interfere%20with,and%20crabs%20and%20other%20crustaceans

Officer, C. T. (2017, September 30). Threat of ocean acidification to echinoderms. Journal of Young Investigators. https://www.jyi.org/2010-november/2011/11/28/threat-of-ocean-acidification-to-echinoderms

Partnering with indigenous communities to anticipate and adapt to Ocean Change. UW News. (n.d.). https://www.washington.edu/news/2018/03/21/partnering-with-indigenous-communities-to-anticipate-and-adapt-to-ocean-change/

Ribeiro, B., Lima, C., Pereira, S. E., Peixoto, R., & Klautau, M. (2023, April 25). Calcareous sponges can synthesize their skeleton under short-term ocean acidification. Nature News. https://www.nature.com/articles/s41598-023-33611-3

US Department of Commerce, N. O. and A. A. (2012, August 1). What is ocean acidification?. NOAA’s National Ocean Service. https://oceanservice.noaa.gov/facts/acidification.html

Wallace, J. (n.d.). The unmatched tides of fundy. Saltscapes Magazine. https://www.saltscapes.com/food-travel-guide/stories/2954-the-unmatched-tides-of-fundy.html

By: Madison Malloy

Sitting at the base of the Bay of Fundy, St. Andrews is no stranger to large tides. The Bay of Fundy sees tides up to 16 metres high, and here in St. Andrews, our tides can rise as high as 8.5 metres (Government of Canada, 2023)! In order to appreciate what causes this phenomenon, we must understand how the Sun and Moon influence tides, as well as the special characteristics of the Bay of Fundy.

How frequent are tides? (National Oceanic and Atmospheric Administration [NOAA], 2013)

The largest tidal force is the gravitational pull of the Moon on the Earth, which pulls the water towards the Moon, forming a bulge. On the other side of the earth, a bulge of approximately equal size is formed from inertia, the opposing force to gravity (NOAA, 2005). In the image above, this is represented by the high tides on either side of the equator, and low tides at both of the poles.

We must also consider the secondary tidal force of the Sun on the Earth. Despite the Sun being around 400 times bigger than the Moon, it has a lesser impact on the tides because it is much, much farther away (Britannica, n.d). The gravitational pull from the Sun creates a smaller bulge in addition to the one from the Moon. Instead of thinking of the tides as going up and down, you can think of the Earth as rotating in and out of these stationary bulges every day.

Spring vs. neap tides (Bay of Fundy, n.d)

Have you ever wondered why the phase of the Moon impacts how high the tides are? It comes down to the position of the Moon relative to the Sun. As seen above, when the Moon, Sun, and Earth are in line, a full or new Moon is observed, and the bulges from the Sun and Moon amplify to make the highest tidal range. This is known as a spring tide, and these are seen twice each lunar month (NOAA, 2014). Also twice each lunar month are neap tides, which happen when the Sun and Moon are perpendicular to each other. This causes the bulges to have a dampening impact, resulting in the lowest tidal range.

Why does the timing of the tides change every day?

First, we need to think about how the Earth rotates once every 24 hours and the Moon rotates around the Earth once every 28 days. Because both the Earth and Moon are rotating, the Earth needs to move a bit extra, around 50 minutes every day, in order to catch up to the Moon. This means that in places with only one high tide a day (diurnal tides), like the poles, the tides come every 24 hours and 50 minutes instead of every 24 hours. Here in St. Andrews, we get two approximately equal-sized tides every day (semidiurnal tides) which come every 12 hours and 26 minutes.

The difference between high tide and low tide outside of the Jolly Breeze Whale Adventures office, St. Andrews

In The Bay of Fundy, home to the highest tides in the world, there are two main features that influence its size. The first factor, the shape of the bay, allows the water to be funneled up and down, creating high tidal levels. Tidal resonance, the process of water being flushed in and out of the bay at perfect timing, allows incoming water to be pushed to high levels. These two factors result in breathtaking tides. We get lower tides at the base of the Bay of Fundy than at the head of the bay, but tides an average of 5 metres high can still be observed here, which tower over the global average of 1 metre (Time and Date, n.d).

Whether you come to St. Andrews for the tides, whales, or lobster rolls, one thing goes without question: St. Andrews would not be the same without the powerful influence of the tides.

References

Encyclopædia Britannica, inc. (n.d.). Understand the relative size of the Sun, the Moon, and other Solar System objects. Encyclopædia Britannica. Understand the relative size of the Sun, the Moon, and other solar system objects

Parks Canada Agency, G. of C. (2023, March 17). Tides in Fundy National Park. Fundy National Park. Tides in Fundy National Park

Spring vs. Neap Tides. Bay of Fundy. (n.d.). Spring vs. Neap Tides – Bay of Fundy

US Department of Commerce, N. O. and A. A. (2005, December 1). Tides and water levels, gravity, inertia, and the two bulges, nos education offering. Gravity, Inertia, and the Two Bulges – Tides and water levels: NOAA’s National Ocean Service Education. Gravity, Inertia, and the Two Bulges – Tides and water levels: NOAA’s National Ocean Service Education

US Department of Commerce, N. O. and A. A. (2013, June 1). How frequent are tides?. NOAA’s National Ocean Service. How frequent are tides?

US Department of Commerce, N. O. and A. A. (2014, August 1). Why do we have spring tides in the fall?. NOAA’s National Ocean Service. What are spring and neap tides?

What causes ocean tides?. The Moon Causes Tides on Earth. (n.d.). What Causes Tides? – Moon

DULSE INFORMATION AND RECIPES

Dark Harbour, Grand Manan Island, New Brunswick

Dulse is a leathery and flat algae, of a deep rose to reddish purple colour.
Dulse is generally harvested by hand at low tide and then spread out to be dried. With sustainable harvesting, they leave a portion behind to regrow, similar to cutting grass.  Harvest season in this area is June to September. Dulse is fast growing especially in mid summer, and can be picked twice a month during the full and new moon.

Dulse is an excellent dietary supplement. One handful provides 100% of the recommended B6, 66% of B12, and high in Floride, Iron, Vit A and C, magnesium and Potassium. It is actual relatively low in sodium!

Grand Manan Dulse is known to be the best Dulse in the world! Thoughts are that the 6 metre high cliffs at Dark Harbour creates a shadow to reduce sunlight and results in darker, thicker and more flavourful Dulse.

It can be eaten as is or mixed into recipes as flakes or a powder.
Try eating Dulse like potato chips in front of the hockey game!
It can also be added to soups.  When pan fried, the smoky flavour can be a reminder of bacon.
Dulse can be roasted in the oven for a crispier and milder flavour.
Add to smoothies, salads, sandwiches, on top of scrambled eggs or popcorn.
Endless uses!

Add Dulse to your sandwich for the best DLT.  Dulse, Lettuce and Tomato sandwich!

In Saint Andrews by-the-sea, we find Dulse at the Spice Box and the local grocery store.

On board the Tall Ship Jolly Breeze, guests can try a piece of Dulse, although admittedly, it can be considered an acquired taste and some gets spit out overboard!

DULSE RECIPES:

NUTRITIOUS MASHED POTATOES
1 medium potato
25 g butter
0.5 – 1 tsp lemon juice
Salt and Pepper
750 ml (1.25 pint) milk
25 Grams Dulse (chopped and soaked in water 5-10 minutes).

DULSE SLAW
Need : 25g Dulse
50g raisins
175g white cabbage (shredded)
1 medium carrot (grated)
2 shallots (finely chopped)
Dressing : 4 tbsp mayonnaise
2 tbsp apple juice
Salt and Pepper
Soak dulse for 5 – 10 mins in a bowl of water.
Put raisins in a small bowl with warm water for 5 mins, to allow to plump.
Put shredded cabbage, grated carrot and finely chopped shallots into a large mixing bowl.
Drain raisins and add to bowl.
Drain dulse, chop and also add to bowl.
In a small bowl mix the dressing ingredients together and then pour over and coat the salad thoroughly.
Season and mix again and serve.

ROASTED CAULIFLOWER DULSE
Cumin Roasted Cauliflower with Dulse (serves 4-6)1 head of cauliflower, trimmed and cut into 2 inch florets
2 tablespoons olive oil
1/4 teaspoon sea salt
1/2 teaspoon cumin
1/2 cup  (pressed together) dried dulse sea vegetable
2 tablespoons chopped green onions
Preheat oven to 425 degrees.  In a large bowl toss the cauliflower with olive oil.  Add sea salt and cumin and mix well.
rrange cauliflower on a baking sheet in a single layer and roast for 20 minutes, stirring twice during cooking time.
While cauliflower is roasting, run dulse under cold water while holding the leaves in your hands.  When all is moistened, turn water off and squeeze out excess moisture.  Chop dulse fine on a cutting board.
Remove cauliflower from oven, place in a serving bowl, sprinkle with chopped dulse and toss.  Top with chopped green onions and serve while  hot. Unbelievably good!   Joanne Carney

WHALE BLOW IDENTIFICATION

Whales can be identified just from their blows, even from a mile away! The different whales have different shapes and heights of their blows.

FIN WHALE: Also known as the Finback whale or Common Rorqual baleen whale.
Very tall and thin column shaped blow up to 6 Metres high.
When feeding, they blow five to seven times in quick succession, but while traveling or resting will blow once every minute or two. On their terminal (last) dive they arch their back high out of the water, but rarely raise their flukes out of the water. They then dive to depths of up to 470 m (1,540 ft) when feeding or a few hundred feet when resting or traveling.

HUMPBACK WHALE:
Shorter bushy, balloon shaped blows that are nearly as wide as they are tall and up to 3 Metres high.
Dives between breaths typically do not exceed five minutes during the summer but are normally 15–20 minutes during the winter.
On average we find on our tours that a Humpback will go down for a dive ranging between 4-7 minutes while feeding and then come up again for about 6-8 breaths and repeat the process
Humpback whales have been known to hold their breath for up to an hour-but we are sure glad they don’t this very often!

MINKE WHALE:
The blows of the Minke whale reach about 2-3 Metres high.
Minke whales breathe air at the surface of the water through 2 blowholes located near the top of the head. At rest, minke whales spout (breathe) about 5-6 times per minute.
They received their common name from a Norwegian novice whaling spotter named Meincke, who supposedly mistook a minke whale for a blue whale.

Locally, we call them ’Stinky Minke’. The term “stinky minke” is a nickname minke whales earned for their odour of rotten fish. Perhaps some chemical in fish or krill also makes it into whales’ bloodstreams, giving their exhalations fishy odours. It is a really ‘special’ experience to smell the breath of a Minke whale from downwind!

NORTH ATLANTIC RIGHT WHALE:
The Right Whale is known for the V-shaped blow caused by the widely spaced blowholes on the top of the head. The blow rises 5 m (16 ft) above the surface.

‘Thar she blows!’.

Why can you see the whales spout when it breaths?   
In baleen whales, the blow holes are in pairs. It is homologous with the nostril of other mammals, and evolved via gradual movement of the nostrils to the top of the head.
Guests can see plumes of mist shoot out of a hole in its head from a mile away at times. Contrary to popular belief, that’s not seawater. It’s actually a cocktail mix of hot air and bacteria.
As a whale breaches the surface, it opens its blowhole and then forces warm air from the lungs into the cold atmosphere. The temperature change triggers water vapour in the whale’s breath to condense into water droplets.The same phenomenon happens when you exhale on a cold day.
Scientists collected samples from 26 humpback whales. Within the spouts, they discovered 25 microbial species. The species were different from what was in the seawater indicating that they came from the whale’s respiratory tract. This is the first step in understanding respiratory disease in whales.

Seastars have an amazing ability to regenerate a limb if one is lost due to predators, trapped by a rock or other reasons. Much is research is being done on this regeneration process. We, as humans, cannot yet regrow a limb! The following explains the 3 basic phases of regeneration limb growth.

Seastars have a main central disk with limbs radiating out. Each limb contains a copy of vital organs. The underside of the seastar is where the mouth and their tube feet reside. They also have ‘eye spots’ (light sensitive organ) at the end of each of their arms. Due to the multiple copies of the organs inside their arms this enables the seastars to be resilient to limb loss and continue to survive long enough to grow replacements.

Seastars can lose limbs due to predation, or due to self-amputation either to escape or for reproduction. When the limbs of a seastar are removed, a seastar can begin to regrow another to replace the missing one. This process takes months to over a year to complete.

While regeneration can vary between individuals, the regeneration process typically follows three main patterns.

1. Unidirectional regeneration, which is the most common, is where a sea star can regenerate limbs as long as more than half of sea star is still intact.
2. Disk-dependent bidirectional regeneration where a seastar can regenerate when less than half of the seastar is intact, as long as a portion of the central disk is still present.
3. Disk-independent bidirectional regeneration is the most complex and extensive process which is when a seastar can regenerate an entire body from a limb even if the central disk is not present. While there are three different types of regeneration, each process follows a generalized process of regrowth which has three phases. A repair phase, an early regenerative phase, and an advanced regenerative phase.

PHASE 1 : REPAIR.
Repair begins with sealing of the coelomic canal to prevent any further fluid loss and to stop foreign pathogens from entering. This is done by the arm wall contracting and coelomocyte cells converge to form a clot and may take care of any foreign debris via phagocytosis. In the following 48 hours, epithelial cells begin stretching inwards from all around the wound to the middle until a continuous layer is formed resulting in new tissue over the wound site. The tissue at the wound also becomes increasingly thicker and more permanent over the next while. The end of the repair phase is marked by a temporary edematous layer where fluid is retained along with important cells, which as it matures over time is the scaffolding for regenerative growth.

PHASE 2 : EARLY REGENERATION.
Once the injury has been healed the early regeneration phase begins. In this phase the coelomic cavities are the main physical driving force. The excess fluid from the coelomic epithelial tissues causes the enlargement of component cells that produces a pressure for support in the regrowing canals and also creates a turgidity that physically supports the regenerate’s shape until skeleton and muscle formation can start. There is an outpouring of dedifferentiating muscle cells towards the regenerating tip and the influx of cells supports the outgrowth of the radial nerve cord from any existing nerve cord remaining post amputation. Early skeletogenesis also begins during the early regenerative phase as plates of calcium carbonite deposit into the collagen network developing in the former fluid retention area. Importantly, near the end of the phase, a small regenerate appears and the pressurized radial water canal starts regenerating the terminal tube foot which is the first defined structure to regenerate.

PHASE 3: ADVANCED REGENERATION.
This consists of the regenerate starting to morph into a little arm approximately 3-6 months post amputation which will continue to grow over its lifetime. This regeneration of the new arm starts the development of structures at the father away point and this acts as a signalling point of the rest of the regrowth. Massive formation of muscular tissue occurs as well as a basal lamina forming around the muscle tissue to separate it from the coelomic cavity. Then, starting from the terminal tube foot, other musculoskeletal structures will form from the tip. This will continue until regeneration is complete. Movement becomes functional again as the nerve cord finishes and the rest of the central nervous system becomes complete. Over time the photoreceptors will develop again leading to full restoration of the optic cushion, finishing off the regeneration of the seastar.

This regeneration process, including regrowing a new limb, is an amazing capability of Seastars!

Linnea Shiell (Bsc marine biology), Joanne Carney

Jolly Breeze Whale Adventures

By: Mahé Colas and Joanne Carney

The Bay of Fundy is home to 7 species of sharks, and 3 of them are in the Mackerel Family with hundreds of individuals, including the impressive Great White shark, and its close relatives the Porbeagles and the Mako Shark. Although mackerel sharks are large and heavy, they are very agile and active fishes that are fast swimming. They typically have long conical pointed snouts, spindle shaped bodies, huge gill openings and they generally have a white ventral surface from the head to the tail.

*FUN FACT: you can track recently tagged sharks at the website ‘Ocearch.org’.

MACKEREL SHARK DIFFERENTIATION:

PORBEAGLE SHARK (Lamna nasus:) can measure up to 3.5 metres (~11.5 feet) and weigh 230kg (~507 lbs). They are mainly recognizable for their distinctive white rear tip on their first dorsal fin. They also have a crescentic/lunate caudal fin with two keels, which is used for easier movement in the water and strength. Finally, their pointed blade-like teeth with smooth edges and lateral cusplets (small bumps on either side of the tooth) are all identical through the entire jaw.

Porbeagle shark: note white on dorsal fin.

Porbeagle sharks are coastal species and found in temperate and cold-temperate waters but can be found to 700 metres underwater (2300 ft). Due to their large size porbeagle sharks do not have any known natural predators however their meat is highly valued by target fisheries. They are not only threatened by commercial fishing activities but also bycatch, which is the unintentional capture of species during fishing. In addition to the enormous fishing pressure, the late age of reproductive maturity and few offspring per pregnancy, (around 4 to 5 pups), they have been listed vulnerable to extinction since 2006.

* FUN FACT, all sharks must swim constantly forward to breathe and gain a constant uptake of oxygen.

2) MAKO SHARKS: can be divided into two species the Shortfin Mako (Isurus oxyrinchus) and Longfin Mako (Isurus paucus). The Mako sharks are slightly larger than porbeagles and can reach a maximum size of 4 metres (~13 feet). They have a deep blue to purple skin color and a large caudal fin with only one keel on the caudal peduncle. Mako’s are highly migratory and capable of withstanding significant temperatures changes due to their specialized blood vessel structure called counter current exchanger. It allows them to maintain a body temperature higher than the surrounding water giving them a lot more flexibility to hunt in colder waters. They have a white underside that covers their slender body and an acutely conical pointed snout. This hydrodynamically efficient body shape and their ability to orient their scales (dermal denticles) makes them the fastest shark in the world, also known as the peregrine falcon of the sea because it can reach 43 mph (70 km/h). Their large U-shaped mouth hold large awl-like teeth that present no cusps or serration, and the lower teeth protrude outside of the mouth even when closed.
The shortfin mako which is classified as vulnerable due its popularity for shark fin soup and bycatch in longline fisheries.

*FUN FACT: There are around 470 species of sharks in the world with the oldest one being a 400-year-old Greenland shark recently discovered by scientists.

3) GREAT WHITE SHARK: (Carcharodon carcharias): They are notable for their large size, with larger female individuals growing to 6.1 m (20 ft) in length and 1,905–2,268 kg (4,200–5,000 lb) in weight at maturity. They have a muscular and heavy spindle-shaped body, a moderately long conical snout, long gill slits, large and triangular dorsal fin without a white rear tip and only one keel on the caudal peduncle of the crescentic caudal fin. The name is thought to have come from their stark white undersides. They have a grey dorsal area (sometimes in a brown or blue shade) that gives an overall mottled appearance.

Great white shark (eating a seal..). Note extensive size.

The lifespan of great white sharks is estimated to be as long as 70 years or more. Great white sharks can swim at speeds of 25 km/hr (16 mph) for short bursts and to depths of 1,200 m (3,900 ft). Great white sharks, like many other sharks, have rows of serrated teeth behind the main ones, ready to replace any that break off. When the shark bites, it shakes its head side-to-side, helping the teeth saw off large chunks of flesh. These sharks, like other mackerel sharks, have larger eyes than other shark species in proportion to their body size. The iris of the eye is a deep blue instead of black.

Great white sharks are known to spend increased amounts of time near the seal rookeries along the Atlantic Coast with seals being one of their food sources. It is not recommended to swim near a seal haul-out or rookery! (see photo!). They are arguably the world’s largest predatory fish, preying on mammals as large as baleen whales.

The species faces numerous ecological challenges which has resulted in international protection and is listed as a vulnerable species. They should be afforded protection because of their ecological role in the ecosystem as an apex carnivore in the food web.

The diversity is immense and there is so much more to learn about these predatory fish to protect them as they play an important role in the balance of the ecosystem.

By: Mahé Colas and Joanne Carney

Four species of seals, including grey, harbour, harp and hooded seals, are commonly observed on shorelines around the Maritime provinces.

On our whale watching tours, the seals are often spotted lazing about on the rocky islands in the middle of the Bay of Fundy. These seal haul out locations are called ‘seal rookeries’ or ‘seal haul-outs’.

The term ‘rookery’ can be applied to a colony of breeding animals such as seabirds, marine mammals, and turtles. While the term rookery originally came from the nesting habits of rooks (a species part of the crow family). Here in the Bay of Fundy, there are many seal rookeries where large aggregation of harbour seals and grey seals can be observed between two high tides cycles.

The behavior of temporarily leaving the water between foraging (hunting) periods to spend time on land is typically associated with pinnipeds. Pinnipeds are a group of marine mammals that include seals, sea lions, fur seals and walrus.

These individuals haul themselves out of the water at low tide on these rocky ledges. These seal rookeries are used for reproduction, mating and giving birth. They are also used for avoiding predators, thermoregulation, socializing, moulting, nursing, resting and removing parasites.

Different seals species may have different haul-out patterns depending on physical constraints like air temperature, wind speed and time of day. In addition to these, there are also biological constraints such as moulting, age and sex and geographical limitations that could affect the range and number of individuals at one location.

Seals are known to be extremely agile in the water and super clumsy on land. They take full advantage of these rocks up until the last second. They can be found laying in a banana shape balancing themselves on the rocks until they get pushed off by the incoming tide. Once the tide is high and covers these rocks, the seals are usually out hunting but at a higher risk to be preyed on by great white sharks and other predators in the surrounding waters.

The newborn seal babies, are generally born on these rookeries in the spring. They are born at low tide and must learn to swim with hours of birth before the tide rises again! Mothers will typically nurse the pups for 4-6 weeks. In their early weeks of life, the mother harbour seal may carry the pup on her back while swimming and diving.

The rookeries are also used for moulting once a year, when a seal sheds their old coats and grow new skin and hair. During this time, the seals spend a particularly large amount of time ashore on these rocky rookeries and spend little or no time feeding in the water. By staying ashore, they minimize heat loss and maintain a relatively high temperature, which encourages blood flow close to the skin, thus accelerating the molting process. More seals will be seen hauled out at low tide on the rocks during the moulting period generally last summer to early fall.

Contrary to popular belief, the seals, when hauled out, are not simply “basking in the sun”. We know this because seals in temperate regions haul out regularly even on the coldest winter days, and seals in polar regions remain hauled out on the ice, even during the most ferocious storms.

Come and enjoy watching the seals hauled out on the rookeries of the Bay of Fundy!