Course:CONS200/2019/Anthropogenic Impacts on Sperm Whales: Implications for Conservations

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Anthropogenic Impacts on Sperm Whales: Implications for Conservation

In the following sections, anthropogenic impacts on sperm whales with be examined in regard to sperm whales life cycle and the key disruptions to the species, with analysis of stakeholders and conservation mechanisms affecting and being affected by the current circumstance of the global sperm whale population.

Introduction

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The expansion of anthropogenic impacts on ocean environments causes increasing concerns for sperm whale populations. Sperm whales can potentially be impacted by anthropogenic effects such as oceanic temperature rise, hazardous fishing methods, and dangerous actions by oil industries. These obstacles could cause disruption in the global sperm whale population and their resulting migration patterns and distribution.

Conservation efforts towards sperm whales are diverse around the world and species endangerment classification also varies.  In fact, recognition of sperm whale populations can be so distinct that some regional government agencies consider sperm whales endangered[1], while other regional governments do not recognize the sperm whale species as at risk [2].Despite regional differences, there are conservationist organizations around the world that aim to protect and survey sperm whale populations and inform the public on endangerment concerns[3][4][5]. If no remedial actions are taken against the disruption of the sperm whale population, then the sperm whale species could be vulnerable to extinction. Additionally, the marine ecosystem would face drastic externalities from losing a key apex predator species.

The Life Cycle of Sperm Whales

Whether you know them from your required reading of ‘Moby Dick’ in high school, or just from general intrigue due to their unique and ancient looking shape, Sperm Whales are some of the oldest creatures on Earth. Yet, much is still unknown about them due to the sheer size of the ocean and the extremely deep depths they dive to. Sperm Whales, given their name unique name from the large amounts of spermaceti held inside of their heads, are some of the biggest animals this Earth has ever known, Sperm Whale[6]. Throughout this section their life cycle will be discussed, including predators, reproduction, diet, migration/social patterns, and general facts.

Sperm Whale hunting became popular in the 1700’s, but it reached its peak in the mid 1900’s, in which it is believed that more than 20,000 Sperm Whales would be killed each year for their various uses[7]. Mainly they were hunted for their spermaceti, a waxy thick substance that fills their large blocky head[7]. Originally this substance was thought to be semen, giving the whale its infamous name. In reality, this substance is a thick oil which can be used for many human purposes, including cosmetics, lamp fluid, soaps, and candles[7]. The oil isn’t the only part of the whale to be used, various parts of their body and blubber have also been used for dog food, cattle feed, vitamins, glue, and even brake fluid[7]. The wide array in which their oil can be used makes hunting sperm whales, unfortunately, the most economically profitable choice. It wasn’t until 1982 that the International Whaling Commission stepped in to monitor and reduce the amount of commercial whaling being done on these defenseless creatures[7]. The committee's involvement has done its job in reducing the amount of Sperm Whale deaths per year, but nothing will return the population of 360,000 Sperm Whale back to its original population of over 1 million[7]. However, humans are not the only enemy of Sperm Whales. Sperm whales have faced attacks from killer whales, false killer whales, and pilot whales[8]. Typically these predictors will only go after a calf, as adult sperm whales grow so large and strong, making them impossible to kill. It is even speculated that giant squid are a threat to sperm whales. Despite no attacks ever being observed by humans, some sperm whale bodies have been spotted containing large, ring-like scars which could only belong to a giant squid[8]. It is believed these scars are a result of sperm whales hunting these giant squid, and as one could imagine, giant squid are capable of putting up a very strong fight.

Male Sperm Whales reach sexual maturity at the end of their teenage years, while females often begin mating before the age of ten[8]. Once the female whale is pregnant with a single calf, the gestation period for her calf is a long 15 month time[8]. This long pregnancy allows the calf to reach an enormous birth length of thirteen feet (4 meter). The combination of long pregnancies and extensive maternal care, only allows a female Sperm Whale to reproduce every 4 to 20 years, but it is typically the latter of the two[9]. Females will reproduce until they are around the age of 40, unlike males who don’t even reach their maximum size until the age of 50[8]. Both males and females have a lifespan similar to humans, on average living to the age of 70[10]. The Sperm Whale reproduction rates are part of what makes their species so vulnerable to whaling. A mother sperm whale spends many years, and copious amounts of energy devoted to raising very few calfs. Then if one were to be killed, not only would all of the mother’s hard work and energy be for nothing, but it would take her many years to reproduce and raise a successful and successful calf once again.  

The Sperm Whales sheer size, and unique physical characteristics, allows them to be very effective predators. Their 50-60 foot bodies are easily recognizable from any other whale species, due to their large block shaped head, and long powerful jaw lined with sharp teeth[11]. Their blocky heads hold the largest brain of any animal on the planet, along with the most advanced sonar system[11]. This sonar system contributes to their advanced hunting abilities, in which they dive to depths of 1200 meters, and are able to sustain a dive for up to two hours[11]. During these long dives, their echolocation allows them to pinpoint their desired pray's location. This technique makes them extremely effect, effective, and deadly predators. In fact, the sperm whale generates the loudest animal made sound on Earth[11]. With several hunts a day combined with their techniques, Sperm Whales consume around 2000 pounds (900 kgs) of food per day. Their daily food intake is made up of 80% squid, while the remainder could be filled with octopus, fish, shrimp, crab, and even small sharks[12].

Sperm Whale migration patterns are still largely undocumented, but most Sperm Whale activity has been captured in the Sub-Arctic and sub-Antarctic waters. Sperm whales migration is extremely difficult to observe, as their sole purpose for travel is to hunt. Hunting is done at such deep depths it makes it impossible to document and track, after all their main food source is the giant squid, another mysterious creature. Only the male Sperm Whale will make the journey to colder waters near to poles in order to hunt, while the females and offspring stay in tropical or temperate waters[11]. The male Sperm Whale is a very solitary creature, only socializing during mating times, other than that females have the primary role in childcare. In fact, female whales with gather with their babies in pods of around 20[11]. In these pods the females share duties, including taking turns hunting, care-giving, and protecting the pod because calves cannot handle deep dives at a young age[11]. In these pods, any young males will break off from the pod at the age of 4, leaving it to be all females once again[11].

Migration Patterns of Prey

Anthropogenic Impacts and Population Endangerment

Direct Effects of Climate Change

The rise in global temperatures are starting to have a direct impact on oceanic species and their geographical locations due to the warming waters. Marine cetaceans have their respective climatic preferences and the global change in climate results in the expectation for respective species to adjust accordingly[13], as seen in the Ligurian Sea where the sperm whale distribution is changing in response to the warming waters [14]. The rising temperatures in waters are beginning to affect species geographical area covered where an ecological relationship exists between a species’ range and population size; the smaller the geographical range and smaller population size of a species, the greater their risk of extinction [15]. A sperm whale's range, among other cetacean species, is also largely determined by the distribution of their prey which are more heavily affected by the warming temperatures which in return has an effect on the whales[16].

The Physeter macrocephalus is considered a cosmopolitan species due to their lack of preference between warmer and cooler oceanic waters[14]. Due to their seasonal migration patterns, they tend to spend most of their time in the midlatitudes and are often found migrating towards the poles to leave the tropical waters in the summer[16]. However, there is no apparent or obvious migration pattern for these sperm whales found in tropical and temperate areas[17] for this species' migration patterns are reliant on those of their prey. Since this species is found to be one of seasonal migration, their migration patterns will not be substantially affected by global climate change. However, female and infant populations are found to be limited to tropical waters and therefore are predicted to experience a poleward expansion for they are cooler and warmer water limited[1].

C: Estimated Current Range of Female Sperm Whales D: Predicted change in Female Sperm Whale Species Range

Indirect Effects of Climate Change

The northwest atlantic ocean, more specifically the U.S. Northeast Continental Shelf is experiencing a dramatic change in ocean temperature due to global climate change[18]. Since sperm whales are found in all ocean waters with a higher density in the mid latitude regions, it is difficult to determine how they are directly affected by a change in ocean waters. However, they are indirectly affected by this change in climate due to the change in migration patterns of their prey. As a result of the warming waters, the prey of sperm whales (including giant squid, other squid species, fish, cuttlefish, and some sharks), are found to be in a lower supply.

Data collected from the U.S. Northeast Continental Shelf displays a change in ocean temperatures at about 3 degrees Celsius in fall seasons[18]. This change in temperature along the coast has resulted in a decrease of suitable, thermal living conditions for the longfin squid (Doryteuthis pealeii), where they are found to be increasing their distance from shores, moving towards the greater oceans, but also found to be low in abundance. In addition, the swordtip squid (Urotheuthis edulis) in the southern Sea of Japan indicated a negative effect in response to sea surface temperature and the Chinese golden cuttlefish, who have a cooler water temperature preference, have also been experiencing a negative effect in terms of growth, population size, and development due to the warming waters[19]. These factors all have a negative effect on sperm whale diets. Although sperm whales are one of the deepest marine mammals (males diving up to 1,200 meters deep and females nearly 1000 meters) they still need to return to sea surfaces for air and recovery[20]. Where prey of sperm whales are found to be retreating to the poles for cooler water conditions or to deeper depths, sperm whales follow. Although sperm whales can dive up to 915 meters for hunting purposes[20], if such species populations continue to relocate to deeper depths, sperm whales may not be able to sustain those depths where they may find themselves in an oxygen deficiency.

Fall Change in Thermal Habitat Abundance for Sperm Whale Prey: Longfin Squid

Fisheries

The following pertains to the mediterranean subpopulation of sperm whales. The fishing industry is found to have a direct effect on the lifespan of sperm whales. The location of fishing as well as the use of drift nets are found in areas with high sperm whale populations. Sperm whales are found to get entangled in fishing gear that is both being actively used as well as those that get abandoned by fishing boats.[21]

Additionally, the unsustainable mass commercial fishing industry could have impacts on sperm whales diets and available food for consumption. With exponential and aggressive commercial fishing actions, available food for sperm whales is diminished as their food sources are being depleted by humans, and also by wake and sound disruption and destruction of spawning habitat from boats[22]. In a study in Australia from 1992-2006, out of 114 beached whales in four locations, 26% of these whales had empty stomachs[23] . This devastation could be related to the effect of mass fishing and/or disruptions from boats on cetacean's population condition.

The Oil Industry

The oil industry is one of the top contributing actors responsible for the existing threats to sperm whale populations[3]. Oil and Gas companies use Seismic surveying methods which are a significant source of anthropogenic noise pollution[4]. The noise pollution interferes with whales’ communication and is correlated with terminal starvation among mature females and calves, abortion in mature females[3] and in extreme cases mass abandonment[4].

Sperm whales are considered a deep diving marine mammals that face challenges in regards to survival requirements: food and air; they must travel to great depths to hunt for their prey while also returning to surfaces to breathe. Due to the dark conditions at such depths, sperm whales rely on echolocation, producing sound waves to predict object’s locations therefore adjusting paths, to detect and locate their prey (Farmer, et al., 2018). However, the rise in anthropogenic noise pollution through Seismic surveying methods and other factors are reducing sensory volumes that are needed by the sperm whales to locate and obtain their prey.[24]

Mass oil spills have significant consequences on Sperm whale populations, a study done in the Gulf of Mexico suggested that oil contamination in the region could have up to a 26% decline in whale populations by 2025[3]. Oil spills also contribute to infant mortality and reproductive failure[3].

Vessel Traffic

Map of Sperm Whale Migration Patterns and areas of interest
Marine traffic in comparison of sperm whale migration routes

Sperm Whale migration varies between male and female whales, but common routes are characterized by breeding and feeding hotspots. In the winter, sperm whales reside in breeding areas such as the Philippines, Hawaii, and Mexico and South America[25]. In the summer they migrate to the North Pacific Ocean to feed[25]. Pacific Ocean vessel routes are concentrated at North Pacific Great Circle Route[26], the Panama Canal[27], and the Strait of Malacca [28]. These vessel routes coincide with sperm whale migration routes during summer months, which can cause distress to sperm whales in a variety of ways. These main shipping routes are subject to high amounts of vessel transportation year around. The Strait of Malacca accounts for 40% of world trade transportation every year[28], and the North Pacific Great Circle Route and the Panama Canal see tens of thousands of ships annually[27][26]. Since whale migration routes and popular vessel routes can overlap, it is possible that Sperm Whales can be affected by vessel strike, ship acoustics, and ship fuel emissions[29]. This vessel related activity could possibly affect ecological structure including the local food web[29], water quality[30], and whale safety[30][29] in such congested areas. Although whale-strike events and ecosystem structure in relation to sperm whales are widely undocumented, it is possible that vessel conflict with marine life needs further investigation.

The following maps highlight routes for sperm whale migration and vessel routes. The first map shows hotspots for sperm whales during migration and breeding seasons[31]. The second map displays vessel routes among the Pacific Ocean accompanied by arrows that show the direction of these routes[32]

As shown in both maps, there is prominent sperm whale migration and vessel traffic close to the Equator and among the Eastern African coast, as well the latitudinal line(45 degrees North) adjacent to Nova Scotia and New Brunswick.

Along research is deficient on the direct impacts on sperm whale migration and vessel traffic, it is evident that there may be vessel related incidents on sperm whales due to high vessel traffic in sperm whales dominant routes.

Implementations and Conservation Concerns

Conservation Status and Implications

Many official government and non government agencies world wide have recognized the anthropogenic threats to sperm whale abundance and have released official legislation and statuses regarding the species’ population conditions. The sperm whale was officially recognized as a vulnerable species in 2008 by the IUCN and is listed on the CITES appendix I and the CMS appendices I and II[33].  The sperm whale is considered endangered under the United States’ Endangered Species Act[1], and is a concern of many other regions including the Caribbean Islands[34], and the Mediterranean Sea[4]. It is important to note that Sperm Whales are not of concern to all nations. For example the species was designated in Canada as a species “not at risk” by COSEWIC in 1996[2].

One of the biggest contributions that can be made towards the conservation of Sperm Whales is through the regulations that currently exist due to the Sperm Whale's international conservation status[35]. Sperm Whales being listed under CITES appendix I establishes internationally, that the trade of Sperm Whales is only allowed under specific permit, which will only be issued if the trade is vital for the survival of the species[36]. Sperm Whales status under CMS appendices I and II provides that international members must protect the species through the prohibition of fishing, and the removal of any obstacle or controlling factor to migration, habitat and breeding [37]. The implications of these two statuses begin to address the effects of the three industries having the greatest significant impact on the species. If enforced, the removal of any obstacles to Sperm Whales will require fisheries to avoid contact with Sperm Whale patterns limiting the damage in which the fishing nets and traffic methods may cause[35]. Furthermore, the oil industries should also be required to modify their practices in order to ensure minimal interference with Sperm Whales. By simply following the existing regulations the current threats to Sperm Whales will be significantly minimized[35].

Sperm Whale Conservation Strategies, Efforts and Industry Involvement

Specific Sperm Whale conservation occurs mainly through the legal protection acquired through their international conservation statuses. Broad Focused conservationist organizations, as well as sperm whale specific NGOs both seek to protect sperm whale populations. The main efforts towards monitoring and restoring Sperm Whale populations have been relatively limited and geographically diverse. Significant research has been conducted in the Mediterranean Sea[4] [5],and in the Gulf of Mexico[3], although much of the recommendations are reliant on encouraging further enforcement of pre-exisitng agreements[35].

In terms of efforts made by governments, the most significant contributions have been made by the U.S. National Oceanic and Atmospheric Administration. Due to the Sperm Whales endangered status under the ESA, it is legally obligated that NOAA establish and implement conservation recovery plans for Sperm Whales[38]. They have done so by strategically addressing the threats to Sperm Whales as well as educating the public and continuing further research into the ongoing anthropogenic effects on Sperm Whales[38].

Although not all nations view Sperm Whales as endangered, it is important to note the role in which they play to greater conservation. Not only do sperm whales play important roles in their local ecosystems, but they also play a great role in global nutrient cycling[39]. Their most important role in nutrient cycling is as a store for oceanic carbon.[39] The decline and removal of sperm whales from the ocean can lead to a significant decrease in oceanic carbon supply [39]. As recent studies suggest the oceans carbon cycle acts as a significant sink in storing atmospheric carbon[40], and therefore the loss of this important aspect of storage could have significant adverse impacts on climate change.

Consequences of Conservation Efforts

As conservationists are the primary protectors for the species, it is important to also highlight that some conservationist activities also can have negative impacts on sperm whales. Many conservationists conduct research that requires survey equipment, which like the surveys conducted by the oil industry, can pollute the ocean with harmful anthropogenic sounds [3]. While conducting research ocean vessels also run the risk of collision with sperm whales, which is on of the primary threats currently facing populations[4]. In order to continue to improve population conditions, it is vital that conservationists are acutely aware of the consequences of their own actions.  

Conclusion

The majestic and primitive sperm whale is known for their large size, spermaceti filled heads, and deep depths they can dive to. Even with increasing research on sperm whales, there is still a-lot of information unknown about the marine apex creatures. As research increases, further knowledge about the anthropogenic impacts for sperm whale are becoming more prominent globally.

With drastic alterations to earth's systems in the recent decades, Sperm whales are becoming more and more scare, and are considered vulnerable by UNC Red List and the ESA, with belief that there are less than 2500 mature whales in the wild[4]. In the United States, sperm whales are considered endangered by the  United States’ Endangered Species Act[1]. In a global context, the sperm whale is recognized as a vulnerable species by the International Union for Conservation of nature[33]. The possible species population decrease can be attributed to anthropogenic processes, including ocean temperature rise[41], exacerbated oil spills and technology, and hazardous fishing methodologies, which could impact sperm whales lifespan and reproduction, diet, habitat, species range (sub-species diversity)[41] and possibly migration patterns[1]. Even though global conservation efforts are diverse, there has been abundant research in the Mediterranean Sea[4][5]and in the Gulf of Mexico[3] regarding sperm whale protection and conservation management . Although research can be limited due to unknown migration patterns and cross continental boundaries, concern still lies for cetaceans with more particular ocean temperature preferences, especially female and infant cetaceans, which primarily prefer warmer waters[1]. Sperm whale conservation is an important effort to maintain healthy oceanic ecosystem, especially with sperm whales roles in nutrient cycling[39]. Sperm whales contribute in many ways in their ecosystem, which is recognised by many conservationist movements around the world. Even so, it is important to continue research on this topic for further understanding in migration patterns and cetacean living requirements through strategies that acknowledge conservation impacts and restrictions  to effectively help the sperm whale population, and not hinder the species further.

References

Please use the Wikipedia reference style (see Wikipedia:Inline citation). Provide a citation for every sentence, statement, thought, or bit of data not your own, giving the author, year, AND page (when using direct quotes). For dictionary references for English-language terms, I strongly recommend you use the Oxford English Dictionary. You can reference foreign-language sources but please also provide translations into English.

Note: Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in Wikipedia: Writing better articles.[42] (Note that - if you look on the edit screen for this page when you are logged in - you will also see this as an example of how to create a reference!)

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Seekiefer (Pinus halepensis) 9months-fromtop.jpg
This conservation resource was created by Will. It is shared under a CC-BY 4.0 International License.