Since the 1970s the role of fishery bycatch as a factor reducing, or limiting the recov- ery of, marine mammal populations has been increasingly recognized. The proceedings of a 1990 International Whaling Commission symposium and workshop summarized fishery and bycatch data by region, fishery, and species, and estimated the significance of the 'impacts' of bycatch in passive gear on all cetacean species and subspecies or geographically defined populations. A global review of pinniped bycatch in 1991 concluded that incidental mortality in passive gear had contributed to declines of several species and populations. Here we update the information on cetacean gillnet bycatch, assess bycatch data on marine mammals other than cetaceans (i.e. pin- nipeds, sirenians, and 2 otter species), determine where important data gaps exist, and identify species and populations known or likely to be at high risk from bycatch in gillnets. We found that at least 75% of odontocete species, 64% of mysticetes, 66% of pinnipeds, and all sirenians and marine mustelids have been recorded as gillnet bycatch over the past 20-plus years. Cetacean bycatch information in some areas has improved, facilitating our ability to identify species and populations at high risk, although major gaps remain. Understanding of the scale of pinniped and sirenian bycatch has also improved, but this bycatch remains poorly documented, especially at the population level. This study reveals how little is known about marine mammal bycatch in gillnets in much of the world. Even as other significant threats to marine mammals have become better documented and understood, bycatch remains a critical issue demanding urgent attention if there is to be any hope of preventing further losses of marine mammal diversity and abundance, and of protecting, or restoring, ecological health.

/pdf/marine-mammal-bycatch-in-gillnet-and-other-entangling-net-4hrqkyh7v8.pdf

Marine mammal bycatch in gillnet and other entangling net fisheries, 1990 to 2011

Cetaceans are protected worldwide but vulnerable to incidental harm from an expanding array of human activities at sea. Managing potential hazards to these highly-mobile populations increasingly requires a detailed understanding of their seasonal distributions and habitats. Pursuant to the urgent need for this knowledge for the U.S. Atlantic and Gulf of Mexico, we integrated 23 years of aerial and shipboard cetacean surveys, linked them to environmental covariates obtained from remote sensing and ocean models, and built habitat-based density models for 26 species and 3 multi-species guilds using distance sampling methodology. In the Atlantic, for 11 well-known species, model predictions resembled seasonal movement patterns previously suggested in the literature. For these we produced monthly mean density maps. For lesser-known taxa, and in the Gulf of Mexico, where seasonal movements were less well described, we produced year-round mean density maps. The results revealed high regional differences in small delphinoid densities, confirmed the importance of the continental slope to large delphinoids and of canyons and seamounts to beaked and sperm whales, and quantified seasonal shifts in the densities of migratory baleen whales. The density maps, freely available online, are the first for these regions to be published in the peer-reviewed literature.

/pdf/habitat-based-cetacean-density-models-for-the-u-s-atlantic-2vr6gz4ira.pdf

Habitat-based cetacean density models for the U.S. Atlantic and Gulf of Mexico.

Entanglement in non-mobile fishing gear has been identified as one of the leading causes of mortality in North Atlantic right whales Eubalaena glacialis. To investigate this issue further, all available photographs of right whales taken from 1980 to 2009 were examined for evidence of entanglement with gear used in fisheries based on presence of rope or netting on the whale or scars inferred to have been caused by an encounter with rope. Photographs of 626 individual whales were assessed and 1032 unique entanglement events were documented. Of the 626 animals, 519 (82.9%) had been entangled at least once and 306 of the 519 (59.0%) had been entangled more than once. Males and females were entangled at similar rates. Juveniles were entangled at a higher rate than adults. On average, 25.9% of adequately photographed animals acquired new wounds or scars from fishing gear annually with no significant trend over time detected. However, the annual percentage of animals observed with rope on the body increased significantly during the study period, suggesting that it is becoming more difficult for whales to free themselves completely from fishing gear. Such high annual rates of entanglement remain a serious conservation concern for right whales because entanglements can have both lethal and sub-lethal effects. Federally required changes to fixed-gear fisheries in US waters have not reduced serious injuries and mortality to legally required levels. Here we show how documenting various annual rates of entanglement can monitor progress and impacts that fishing gear regula- tions may have on right whale recovery.

/pdf/monitoring-north-atlantic-right-whale-eubalaena-glacialis-4e9ble965k.pdf

Monitoring North Atlantic right whale Eubalaena glacialis entanglement rates: a 30 yr retrospective

Publisher Summary This chapter discusses the characteristics, taxonomy, distribution, abundance, and ecology of the humpback whale or Megaptera novaeangliae. The humpback whale is one of the best known and easily recognizable of the large whales. It is known for its frequent acrobatic behavior and its occasional tendency to approach vessels. At close range, humpback whales are easily distinguished from any other large whale by their remarkably long flippers, which are approximately one-third the length of the body. The flippers are ventrally white and can be either white or black dorsally depending on the population and the individual; the flippers of North Atlantic humpbacks tend to be white, while those in the North Pacific are usually black. Humpback whales are found in all oceans of the world. They are a highly migratory species, spending spring through fall on feeding grounds in mid- or high-latitude waters, and wintering on calving grounds in the tropics, where they do not eat. They are typically found in coastal or shelf waters in summer and close to islands or reef systems in winter. The humpback whale is heavily exploited by the whaling industry for several centuries. Because of its coastal distribution, it is often the first species to be hunted in a newly discovered area. As a result, the humpback is considered as an endangered species.

Humpback Whale: Megaptera novaeangliae

Collisions with vessels are a serious threat to a number of endangered large whale species, the North Atlantic right whale (Eubalaena glacialis) in particular. In late 2008, the U.S. National Oceanic and Atmospheric Administration issued mandatory time-area vessel speed restrictions along the U.S. eastern seaboard in an effort to mediate collision-related mortality of right whales. All vessels 65 feet and greater in length are restricted to speeds of 10 knots or less during seasonally implemented regulatory periods. We modeled mortality risk of North Atlantic right whale when the vessel restrictions were and were not in effect, including (1) estimation of the probability of lethal injury given a ship strike as a function of vessel speed, (2) estimation of the effect of transit speed on the instantaneous rate of ship strikes, and (3) a consideration of total risk reduction. Logistic regression and Bayesian probit analyses indicated a significant positive relationship between ship speed and the probability ...

https://esajournals.onlinelibrary.wiley.com/doi/epdf/10.1890/ES13-00004.1

Vessel speed restrictions reduce risk of collision-related mortality for North Atlantic right whales

This Technical Memorandum contains summaries of presentations given at the 2007 Serious Injury Technical Workshop. These summaries (sections 3.0-6.0) were prepared by the author(s) of the presentations; therefore, statements and recommendations represent the views and opinions of the respective presenter(s). The summaries do not necessarily represent the views of the workshop Steering Committee or the National Marine Fisheries Service (NMFS). The Steering Committee did not make any substantive changes to the summaries without permission from the author(s). The Steering Committee edited the summaries only to correct grammatical errors and other minor edits. This Technical Memorandum contains summaries of plenary and subgroup discussions that occurred during Days 1-3 of the workshop. While many of the comments and suggestions provided by the individual participants represent shared opinions among the participants, the intent of these discussions was not to reach consensus recommendations. Instead, the intent was to gather input from each individual participant based on his or her expertise and experience. For this reason, the discussions summarized in this Technical Memorandum do not represent consensus recommendations from the workshop participants to NMFS. This Technical Memorandum contains recommendations of Federal Government participants and the workshop Steering Committee concerning the guidance and process for distinguishing serious from non-serious injuries. These recommendations do not represent official NMFS policy. iii Executive Summary Background The Marine Mammal Protection Act (MMPA) section 117 requires the National Marine Fisheries Service (NMFS) to prepare stock assessment reports (SAR) for all stocks of marine mammals that occur in waters under the jurisdiction of the United States. These reports summarize human-caused mortalities and serious injuries to marine mammals by source. In addition, MMPA section 118 requires commercial fisheries to reduce mortality and serious injury of marine mammals to insignificant levels approaching a zero mortality and serious injury rate. This charge requires that NMFS distinguish between injuries that are serious and those that are not serious. NMFS defined " serious injury " in regulations (50 CFR 229.2) as " any injury that will likely result in mortality. " However, the MMPA and its legislative history do not provide guidance on how severe an injury must be to qualify as " serious. " To promote national consistency for interpreting the regulatory definition of serious injury, NMFS convened a workshop in April 1997 to discuss available information related to the impact of injuries to marine mammals incidental to commercial fishing operations (Angliss and DeMaster, 1998). Since …

Differentiating Serious and Non-Serious Injury of Marine Mammals: Report of the Serious Injury Technical Workshop

Guidelines for Assessing Marine Mammal Stocks: Report of the Gamms III Workshop: February 15 - 18, 2011, La Jolla, California

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Differentiating Serious and Non-Serious Injury of Marine Mammals: Report of the Serious Injury Technical Workshop

Guidelines for Assessing Marine Mammal Stocks: Report of the Gamms III Workshop: February 15 - 18, 2011, La Jolla, California