wildlife and offshore drilling sperm whales

8/9/2019 Wildlife and Offshore Drilling Sperm Whales

1/4

S S n Guf f xcSperm whales are leviathans of the sea. Males can reachlengths of 60 feet, and weigh as much as 125,000 poundsabout as much as a fully-loaded Boeing 737. Females aresmaller, rarely more than 40 feet long. ese animals possessthe largest brain of any creature that has ever lived; their hugeheads comprise a third of total body length. eir narrow,rod-shaped lower jaws hold 20 to 26 pairs of well-developedteeth, which are customized for seizing and grasping theirdeep-water prey. Sperm whales can live more than 60 years.

Sperm whales are found in deep waters from the equatorall the way to the edge of pack ice at both poles. For morethan two centuries they were pursued relentlessly by whalersfor their oil (as chronicled in Herman Melvilles classicMobyDick)a hunt that seriously depleted their population. Today,however, the animals are protected under the Endangered

The sperm whale is the most abundant large whale residing year-round in the Gulf ofMexicoone of the busiest, most industrialized bodies of water in the world. In additionto the hazards posed by shipping trafc, commercial shing and fossil-fuel explorationand extraction, sperm whales in the Gulf are faced with a new threat: oil from the BPDeepwater Horizon disaster.

Wildlife and OffshOre drilling

T 2010 Gulf of Mxico Disst: Sm Wl

Species Act, the Marine Mammal Protection Act and theInternational Convention for the Regulation of Whaling.ey are the only whale listed under the Endangered SpeciesAct found in the Gulf of Mexico.

Sperm whales in the northern Gulf of Mexico areconsidered to be a separate stock (or population) from othersperm whales. Recent studies indicate that the Gulf s spermwhales have distinctive acoustic signals used for communi-cation as well as unique genetic markerstraits that oftendistinguish other whales inhabiting semi-enclosed, isolatedbodies of water.

Family groups of females and young totaling 500 to 1,500individuals reside throughout the northern Gulf. Includingvisiting males, the total number of sperm whales in thisregion may be as high as 3,000. Sperm whales in the Gulf ofMexico tend to aggregate only in the deeper waters beyond the

SperM Whae near paTrM n The G Me, phT by hrSTph rhTer r SWSS (MMS).; rG .S. aS


2/4

continental shelf, especially where waters are deeper than about3,000 feet. Sperm whales tend to cluster oshore of the Missis-sippi River Delta and at the Mississippi Canyon, extremelyclose to the site of the BP Deepwater Horizon oil spill.

Foraging and diet

Sperm whales make deep and prolonged dives for their prey,and can therefore use the entire water column. An averagedive lasts about 35 minutes and usually goes down to about1,300 feet, although some dives last over an hour andreach depths over 3,200 feet. Sperm whales feed regularlythroughout the year, consuming 3 percent to 3.5 percent oftheir body weight each day. eir favored prey includes largesquid weighing between 3.5 ounces and 22 pounds each,but they will also eat large, deep-dwelling sharks, skatesand other shes. ey seem to forage mainly on or near thebottom, often ingesting stones, sand, sponges and othernon-food items.

Social and reproductive behaviorSperm whales organize into dierent kinds of social units.ese include nursery groups, in which adult females, bothrelated and not related, travel with sub-adult ospring.Females reach maturity at seven to 13 years of age. Maturefemales become reproductively active simultaneously,usually between March and June. Females give birth toa calf about once every ve to six years. Females andjuveniles generally remain all year in warm tropical waterssuch as the Gulf of Mexico.

Sperm whales also form harem or mixed schools, andjuvenile or immature schools. Males eventually leave groupsas they reach maturity, and live instead in bachelor schools.As males get older, the cohesion of these bachelor groupsstarts to decline. During the prime breeding period and invery old age, male sperm whales are mostly solitary. Males

also wander further into colder ocean waters.

Impacts of oIl

Due to their diving habits, sperm whales are vulnerable todisturbance from oil exploration, industrial development andassociated shipping. Direct oil exposure also poses hazardsto these animals. Contrary to some reports, whales do notnecessarily avoid oil slicks or contaminated habitats. Whaleshave been seen swimming and feeding in or near oil. eanimals strong attraction to specic areas for breeding orfeeding may override any tendency for them to avoid thenoxious oil. Weathered or tar-like oil residues also poselong-term risks to whales.

Research indicate that inhalation of oil droplets, vaporsand fumes are among the greatest risks to whales andother marine mammals, especially if the animals surface inextensive slicks to breathe. Exposure to oil in this way coulddamage mucous membranes, damage airways or even causedeath. Other risks may include: hypothermia due to conduc-tance changes in skin, resulting in metabolic shock; toxiceects and secondary organ dysfunction due to ingestion ofoil; interstitial emphysema due to inhalation of oil droplets

he sperm whale was immortalized i Moby

ick, ad the reatre looms jst as large i

e as i literatre. flly grow males aeah 60 eet i legth ad weigh more tha

0 tos. Sperm whales have the largest brai

ay reatre that has ever lived.


3/4

and vapor; gastrointestinal ulceration and hemorrhaging dueto ingestion of oil during feeding; eye and skin lesions fromcontinuous exposure to oil; weight loss due to restricted dietand stress from oil exposure; and behavioral changes.

Indirect eectsOil development is often associated with the release of a widevariety of other contaminants into the environment. In the BP

Deepwater Horizon spill, additional contaminant risk is posedby dispersants used to break up the oil. By BPs own account,it has mobilized a third of the worlds supply of dispersants,including Corexit, to treat this spill. Dispersants can cause geneticmutations and cancer, further adding to the cumulative eectsof oil toxicity. Levels of mercury, cadmium and other marinecontaminants are already high enough in sperm whale tissue toraise concerns about reproductive impairment in this species.

Impacts of oil spills combined with climate change andother threatsIncreases in global temperatures are expected to have profound

impacts on marine ecosystems and these impacts are projectedto accelerate during this century. Because ocean currents andwater temperatures inuence sperm whale migratory routes,along with feeding and breeding areas, climate change willlikely impact the animals habitat and food availability. Forexample, in the equatorial Pacic there is some evidence thatsperm whale feeding success and calf production are reducedby increased sea surface temperatures.

Other current threats include ingestion of marine debris;chemical pollution; and subsurface noise, including noisecaused by oil and gas development, seismic testing and heavyshipping trac. Sperm whales are known to respond dramat-ically to loud, unfamiliar underwater sounds, such as duringseismic and military testing. Rare causes of natural mortalityin sperm whales include predation, competition and disease,but these by themselves are generally not thought to be

conservation threats. ere are also many documented casesof beach stranding for which the cause is not known.Entanglement in shing nets (including ghost nets)

and collisions with ships represent the greatest direct threatsto sperm whale populations currently. Due to their oshoredistribution and deep feeding habits, sperm whales appearto be much less vulnerable to entanglement with shing gearthan some other cetacean species. Nevertheless, sperm whalessometimes get entangled with oshore shing gear, such aslong-line sheries and pelagic drift gillnets targeting sharks,billsh and tuna. Because they spend long periods rafting atthe surface between their deep dives, sperm whales are struck

comparatively often by vessels.Past whaling and the complex social structure of sperm

whales makes it dicult to accurately assess the creaturespopulation status. Because they range widely in deep watersand stay submerged for lengthy periods, it is challengingto count them. In addition, historical catch records areincomplete or inaccurate. Intensive whaling may also havefragmented the populations of sperm whales.

Sre: naTna Marne ShereS SerVe

s may as 3,000 edagered sperm whales may be

i the orther Gl. rodigios divers, these aimal

most ote od i waters deeper tha 3,000 eetil

the area arod the Deepwater orizo dri

General distribution of sperm whale

sightings from vessel surveys 1996-2001

Sperm Whales in theNorthern Gulf of Mexico


4/4

DEFENDERS OF WILDLIF

1130 17th Street, N.W.

Washington, D.C. 20036

202.682.9400

www.defenders.org

What cItIzens can Do

Support designation of marine sanctuaries and othermarine protected areas where sperm whales and othermarine life are buered from disturbances caused byshipping and industrial development.

Encourage reductions of human-made underwater noise

at sites important to sperm whales. is includes stop-ping seismic surveys when towed air guns are within 1/3mile of whales.

Urge your elected ocials to pass comprehensive climatechange legislation that addresses the impacts of globalwarming on wildlife and our natural resources.

What polIcy makers can Do

Ensure that BP funds long-term research necessary fordocumenting impacts to sperm whales in all Gulf areasaected by the spill, including mitigation for the long-

term damage caused to whales from nonlethal exposure. Support ongoing and additional studies to evaluate the

eects of sound disturbance on sperm whales, includingimplementing regulations as appropriate for mitigatingsound-production activities found to be potentiallydetrimental to sperm whales.

Impose greater safety and environmental standards anddevelop comprehensive spill response plans on existingoshore drilling operations.

Prevent expanded drilling operations o the coast tolimit future spill risks.

Enact comprehensive energy and climate change policiesto transition away from harmful oil and fossil fuels.

Aguilar, A. 1983. Organochlorine pollution in sperm whales, Physetermacrocephalus, from the temperate waters of the eastern North Atlantic.

Mar. Poll. Bull. 14: 349-352.

Ashford, J. R., P. S. Rubilar, and A. R. Martin. 1996. Interactions betweencetaceans and longline shery operations around South Georgia.Mar.

Mammal Sci. 12: 452-457.

REFERENCES

For the latest information on the oil spill, visit www.deedersblog.org

Sperm whales are r

imperiled by etaglemet i

ets ad ollisios with s

alog with the oise ad poll

assoiated with oshore dr

halatio or igestio o o

kill the aimals diretly or le

hroi illess ad orga dam

Beary, J. F., III. 1979. Mercury in sperm whale meat. Science266: 1260.

Christal, J., H. Whitehead, and E. Lettevall. 1998. Sperm whale socialunits: variation and change. Can. J. Zool. 76: 1431-1440.

Davis, R. W., G. S. Fargion, N. May. T. D. Leming, M. Baumgartner, W.E. Evans, L. J. Hansen, and K. Mullin. 1998. Physical habitat of cetaceans

along the continental slope in the north-central and western Gulf ofMexico.Mar. Mammal Sci. 14: 490-507.

Engelhaupt, D. T. 2004. Phylogeography, kinship and molecular ecology osperm whales (Physeter macrocephalus). University of Durham, Ph.D. thesis

Mullin, K. D., and G. L. Fulling. 2004. Abundance of cetaceans in theoceanic northern Gulf of Mexico, 1996-2001.Mar. Mammal Sci. 20:787-807.

National Marine Fisheries Service. 2009. Sperm whale (Physeter macrocepha-lus). 5-year Review: Summary and Evaluation. Silver Spring, MD. 42 pp.

OHern, J. E., and D. C. Biggs. 2009. Sperm whale (Physeter macrocepha-lus) habitat in the Gulf of Mexico: satellite observed ocean color andaltimetry applied to small-scale variability in distribution.Aquatic Mamma

35: 358-366.Waring, G. T., C. P. Faireld, C. M. Ruhsam, and M. Sano. 1993. Spermwhales associated with Gulf Stream features o the north-eastern USAshelf. Fisheries and Oceanography2: 101-105.

Weller, D. W., B. Wrsig, S. K. Lynn, and A. J. Schiro. 2000. Preliminaryndings on the occurrence and site delity of photo-identied sperm

whales (Physeter macrocephalus) in the northeastern Gulf of Mexico. Gulf ofMexico Sci. 18: 35-39.

Whitehead, H., V. Papastavrou, and S. C. Smith. 1989. Feeding success ofsperm whales and sea-surface temperature o the Galpagos Islands.Mar.Ecol. Prog. Ser. 53: 201-203.

apphoTo/GuaMVar

ieTyneWS/chriSbanGS

wildlife and offshore drilling sperm whales

Documents