chapter 14: conservation

conservation goals

what is conservation?

• preserve biodiversity at all levels, including ecosystems

• prioritize the self-renewing capacity of natural populations

• captive breeding, restocking, and reintroduction aid conservation

• artificial settings (e.g. zoos, oceanariums) alone do not ensure conservation

conservatoin goals

• restore species’ natural habitats and migration routes

• maintain genetic diversity to ensure population resilience

• recognize the role of social behaviours in conservation

threats to marine mammals

• overexploitation and commercial hunting

• bycatch and entanglement

• vessel collisions

• climate change impacts

• noise pollution

• environemtnal pollution

• climate change

• human activities

• species at risk

overexploitation and commercial hunting

• steller’s sea cow - hunted to extinction within 27 years of disscovery

• sea otters - near extincction from fur trade in the 18th and 19th centuries

• polar bears - indigenous and non-indigenous hunters

• and vaquita

ongoing direct exploitation

• despite declines in commercial hunting, hundred of thousands of marine mammals are still killed yearly for food, bait, profit or trade

• some communities, like the inuit in USA (alaska), canada, russia, and greenland, practice substinence hunting

• commercial demand continues to drive hunting:

  • polar bears (canada, greenland, Alaska, and russia)

  • walruses (canada, greenland, alaska, and russia)

  • sea otters (alaska and russia)

examples:

• the canadian commercial seal hunt (harp, grey, and hooded seals)

  • 2021: 26 000 seals were hunted

• asian market demand:

  • pinniped penises and bacula (walrus/seal penile bones) in traditional medicine

  • polar bear gall bladders and hides for medicinal and decorative use

• live captures for aquariums and marine parks continue to affect species such as orcas and belugas

indigenous and local hunting traditions

• walrus hunting in alaska, canada, greenland, and russia provides ivory and carvings for trade

• faroe islands hunt hundreds to a thousand pilot whales and hundreds of atlantic white sided dolphins anually

• aboriginal hunters in russia, the US, canada, and greenland yearly kill:

  • several tens of bowhead and grey whales

  • hundreds of belugas and narwhals

  • over 10 000 seals (ringed, bearded, ribbon, harp, hooded, and spotted)

  • at least 10 000 walruses

• these hunts support local economies and international trade (e.g. trophy items, ivory carvings

whaling

• 1990: industrial whaling begins

• 1905 - 1925: improving technology (diesel engine, explosive tipped harpoons) lead to the peak years of the whaling industry

• 1930s: falling demand for whale blubber and whale oil for food (along with growing scarcity of whales) leads to decline of the industry

• 1960s: start of concern over crashing numbers

• 1990s: low point of 5000 blue whales in sea

• present day: sligth recovery. approx. 10 000 blue whales in the sea

hunting

• thousands of manatees are killed in west africa and south america

• dugong hunting persists, legally and illegally, even in near-extinct areas

• sea otter hunting is legal in alaska and increasing; poaching rises in russia

• narwhal ivory is mainly traded internationally for trophies and carvings

marine mammals used for fishing and trade

• marine mammals are used as bait in shark longlines, especially in south america

• crab traps also use marine mammal parts as bait

• river dolphin oil in india and bangladesh used as fish attractant, worsening their decline

protection moratorium 1982

• the international whaling commision (IWC) began in the 1940s to balance conservation and industry

  • failed in 1970s, causing whale stock depletion

• IWC paused commercial whaling due to stock management concerns in 1982

• marine mammal protection act (MMPA) (1972): shaped US conservation policies

  • goal: maintain whale stocks at optimum sustainable population (OSP) levels

  • regulations: commercial whaling banned; subsistence aboriginal hunting allowed

threats from human activities

• whaling in norway, japan, faroe islands, greenalnd, canada, russia, indonesia, and the US removed 81% biomass

norway whaling

• about 70% of the whales targeted are pregnant females

• whales are hunted under an objection to teh global ban on commercial whaling

• only 2% of norwegians eat whale meat regularly

• part of the whale meat ends up in dog food

• tourists are offered whale meat

commercial whaling

• norway and japan continue hunting minke whales:

  • norway - north atlantic

  • japan (commercial whaling since 2019) - antarctic and north pacific

  • both seek to reopen internation whale meat trade and expand whaling

• iceland conducts commercial whaling of fin and minke whales

faroe islands

• drive hunting - hunting of the entire group

• hunt hundreds to a thousand pilot whales and hundred of atlantic white sided dolphins annually

control killing

• marine mammals are seen as threats to fisheries due to competition for fish

• pinnipeds (seals, sea lions) are targeted for interfering with fishing gear, stealing fish, or as competitors

• grey seals are blamed for spreading parasites to local cod and ground fish

• manatees are balmed to raid rice fields and remove fish from gill nets

• polar bears, seen as a threat to humans, are sometimes killed in self-defense

impacts of overexploitation

• excessive hunting left some whale populations critically low, risking uncertsain recovery

• selective removal of males, like sperm whales, has disrupted reproduction and social strucutres, increasing their vulnerability

• some species remain fragmented and isolated at high risk of extinction, even after hunting ceased

bycatch and entanglement

• incidentalcapture in fishing gear remains a major cause of mortality

• ghost fishing gear (abandoned or lost nets) continues trapping marine mammals long after being discarded

• conservation solution: modifying fishing gear and implementing seasonal fishing restrictions

• examples of affected species:

  • north atlantic right whale - threatened by entanglement in fishing gear and ship strikes

  • gray whale - faces entanglement in nets and marine debris

  • also dugongs, monk seals, vaquita, and etc.

vessel collisions

• ship collisions are a major cause of injury and death for large whales, including blue whales and sperm whales, especially in high-traffic areas

• speed regualtions and ship rerouting in migration corridors help mitigate this threat

• florida manatees, frequently injured or killed by boat propellers

• humpback whales, vulnerable to collisions in high-traffic shipping lanes

impact of noise pollution

• shipping traffic, industrial activity, and military sonar disrup communication and echolocation in whales and dolphins

• seismic surveys used in oil exploration cause stress, strandings, and hearing damage

• chronic exposure to underwater noise exposure (boats, military sonar, drilling) can cause:

  • hearing dmage, degraded auditory acuity

  • stress, behavioural changes (e.g. humpback whales avoiding high boat traffic areas)

  • temporary or permanent shifts in hearing thresholds, affecting foraging and communication

• beaked whale starndings linked to military sonar, underwater explosions, and drilling

environmental pollution

• chemical pollutants like PCBs accumulate in marine mammals, affecting health and reproduction

• species at risk:

  • southern resident killer whales - struggling with PCB contamination and reduced prey availabilty

  • beluga whales - bioaccumulate industrial pollutants in arctic waters

• reproductive issues from organochlorine contamination:

  • reported in califronia sea lions, baltic sea grey seals, harbour seals, and belugas

• accumulate heavy metals, pesticides, and microplastics, leading to hormonal imbalances and weakened immune responses

• plastic: ingestions of plastics, particularly in species like sperm whales, causes digestive blockages and malnutrition, or entanglement

• conservation: enhancing regulation to limit chemical and plastic waste entering marine environments

• promoting clean up initiatives and reducing single use plastics to protect marine food chains

• oil spills create marine mammal die-offs, coating marine mammals fur or skin, reducing insulation and causing poisioning when ingested

climate change impacts

• affects species distribution, physiology, and beahviour

• warming impacts ice-depndent species (e.g. walruses, polar bears)

  • less sea ice reduces prey and reproductive success

• ocean mixing changes may lower prey populations

• ocean acidification affects food chains by impacting plankton and shellfish populations

• some species may switch prey or seek less energy-intensive food

• rising sea levels may impact land-reliant species for pupping/lactation

unregulated tourism and human distrubance

• boat traffic, snorkelling, and whale watching tours can stress marine mammals, disrupt feeding and resting behaviours

• some tourism activites such as swimming with dolphins, can alter natural behaviours and disrupt feeding

marine mammals watching

• marine mammals tourism, including whale and dolphin watching, has become a profitable industry

• even whaling nations like japan, norway, and iceland have embraced whale and dolphin watching

• tourism promotes conservation by shifting from hunting to observation

• challenges include:

  • disturbance from tour boats

  • relentless pursuit of animals

  • economic shifts from whale based products to alternatives like farming and aquaculture

alternative solutions

• museums

• media: videos, books, documetaries, movies

conservation efforts

management of marine mammal threats

• clear management goals are neede for regulating killing and capture

• conservation measures must be legitimate and credible

• rules should be fair and based on natural limits

• management must account for uncertainty to prevent miscalculations

mitigatoin of indirect threats

• mitigating indirect threats is challenges, requiring documentation, education, and innovation

• scientific challenges:

  • studying wild marine animals lacks experimental control, elading to debate

• potnetial solutions:

  • modify dams and flood controls to reduce harm

  • dolphin swimways: help river dolphins bypass irrigation barriers

  • devices reduce manatee deaths in floodgates

international conservation agreements

• some species need international treaties for protection:

  • 1973 international polar bear conservation agreement

  • 1980 antarctic marine living resources convection

• commercial whaling governance is controversial

• disagreements exist within teh IWC on small cetecean protection

• marine mammal protection act (MMPA) - 1972

  • first US law protecting all marine mammals

  • prohibits hunting, harrasment, capture, or killing without a permit

  • regulates bycatch from commercial fisheries

  • applies to imported seafood from non-compliant countries

• endangered species act (ESA) - 1973

  • protects endangered marine mammals (e.g. blue whales, hawaiian monk seal, vaquitas

  • requires recovery plans and critical habitat protections

• the wave of international regulations began

conservation efforts

• marine protected areas (MPAs)

  • designated regions where human activities are regulated to preserve marine biodiversity. MPAs play a crucial role in marine mammal conservation by reducing habitat destruction, limiting pollution, and managing resource use

  • species specific protections (e.g. from harrasment)

  • no-take policies (banning hunting / fishing)

  • seasonal or permanent restrictions on human activites

  • effectiveness depends on proper design and enforcement

• examples of MPAs

  • hawaiian humpback whale national marine sanctuary (USA) protects humback whale breding and migratory areas

  • pelagos sacntuary (mediterranean) - a transnational MPA protecting ceteceans from shipping noise and overfishing

  • great barrier reef marine park (australia) - helps conserve dugong populations by restricting harmful activities

  • baja california biosphere reserve (mexico) - safeguards key breeding grounds for grey whales, calves, and managed tourism

• MPA: slatrstarumen, norway

  • teh world’s strongest tidal current

  • MPA since 2013, 24.7 km2 to safeguard habitats and species such as cod, halibut, and monkfish

  • challenges: overfishing and discarded fishing gear threaten the ecosystem

  • 2024: fishing bam on wolfish was implemented to enhance conservation efforts

• important marine mammal areas (IMMAs)

  • specific areas identified as critical habitats for marine mammals based on scientific assesments

  • unlike MPAs, IMMAs do not have legal protections but serve as priority zones for conservation planning

• examples of IMMAs

  • antarctic peninsula IMMA - home to several whale species, including humpbacks and minkes, which are affected by climate change

  • amazon river IMMA - critical habitat for the endangered amazon river dolphin

  • northwest atlantic shelf IMMA - identified for its importance to north atlantic right whales

ecosystem conservation

• conservation should focus on entire ecosystems, not just individual species

• ecosystem-level threats must be addressed alongside direct conservation efforts for indivdual species

• challenges in ecosystem conservation:

  • aquatoc systems are fluid, making boundaries difficult to define

  • limited understanding of ecosystem functions

  • tension between species-focused and ecosystem based conservation affects resource allocation

• best approach: protect species while maintaint ecosystem integrity

  • example: north atlantic right whales face habitat related challneges

  • low prey densities, competition, and pollution

  • major threats: ship strikes and fishing gear entanglement

mortality and habitat challenges

• reducing mortality is critical for species with very low populations

• protecting individuals is essential when natural recovery is unlikely

• immediate threats like gillnet entanglement outweight baitat degredation for some species (e.g. river dolphins)

• adaptable marine mammals can survive in degraded environments but still need protection from human threats

• species focused conservation may overlook species not yet at risk, missing prevention opportunities

• resource agencies often prioritize exploitation over maintatining healthy populations

the role of science in conservation

• science helps define, characterize, and solve problems

• ongoing research refines understanding and predictions

• studies should support goals without delaying action

• policymakers may misuse research to postpone politically sensitive conservation decisions

• the vaquita is the most critically endangered marine cetecean

• funding favours surveys over bycatch threats

• conservation efforts should take priority over excessive research

• compensating fishermen could help reduce bycatch

• surceys and meetings are cheaper than restricting fishing

• governments prioritize jobs over conservation

• research os favoured over controversial action

vaquita

• vaquita - 150 cm, 55 kg

• the smallest and mostendnagered cetecean. in 2023, 8-13 were counted; in 2024, only 6-8

• nearly 1 in 5 vaquitas drown in gillnets set for totoaba, a critically endangered fish from teh upper gulf of california, highly valued on the black market

• conservation measures, including gillnet bams and international trade restrictions, have had limited success due to weak enforcement

baji - yangtze river dolphin

• population declined to a few hundred by the 1980s

• waited too long to counteract habitat destrcution and polluted waters

• experts proposed a semi-natural reserve reuqiring 25 individuals

• the last known captive male QiQi lived alone in a concrete tank

• functionally extinct in 2006

• due to habitat destruction, pollution, and unregulated fishing, the baiji’s extinction underscores the urgent need for better freshwater conservation startegies

conservation strategies and management solutions

conservation efforts

• north atlantic right whale

  • despite being legally protected siince the 1930s, still declining

  • conservation efforts: ship speed restrictions, altered shipping lanes, and ropeless fishing gear aim to reduce human induced mortality

rescue, rehabilitation, and release

• rescue and rehabilitation: used for orphaned or stranded marine mammals, a form of trasnlocation

• public awareness: rehabilitation educates on marine conservation and raises awareness of species threats and environment

• drawbacks:

  • interferes with natural selection

  • risk of disease trasnmission form captive to wild populations

hawaiian monk seal trasnlocation

• relocation efforts: undersized immature females moved from french frigate shoals to kure or midway atoll due to food scarcity

• goal: reduce prey pressure near natal beaches and boost subpopulations

• mobbing issue: young males harassed/killed females while mating

• 1980s-1990s: males trasnlocated form Laysan island to mitigate mobbing, but population decline continued

effectiveness and controversies of rehabilitation

• other programs: conducted with mediterranean monk seals in greece, madeira, and mauritania, but long-term success is unclear

• public awareness: rehabilitation educates on marine conservation and raises awareness of species threats and envornemnts

• drawbacks:

  • interferes with natural selection

  • risk of disease trasnission from captive to wild populations

• policy decisions: as wadden sea seals recovered, denmark, germany, and the netherlands reduced rehabilitation programs

conservation startegies and management solutions

• mitigating human impact

  • marine protected areas (MPAs) and dynamic conservation

  • sustainable fisheries management

  • reducing noise and chemical pollution

  • legal and ethical considerations

  • community engangement and advocacy

conclusions and future directions

• expanding MPAs and IMMAs

• innovative conservation strategies

• addressing climate change

• enhancing global cooperation

• increasing conservation funding

• by integrating scientific research, policy reform, and ethical responsibility, we can ensure the long term survival of marine mammals despite increasing human activity