Fin whale (Balaenoptera physalus)

Abstract To effectively protect and manage marine mammals, contemporary information on their abundance and distribution is essential. Several factors influence present-day insight including the accessibility of the study area and the degree of difficulty in locating and studying target species. The offshore waters of the Gulf of Alaska are important habitat to a variety of cetaceans yet have remained largely unsurveyed due to its remote location, vast geographic area, and challenging environmental conditions.

Mortality from collisions with vessels is one of the main human causes of death for large whales. Ship strikes are rarely witnessed and the distribution of strike risk and estimates of mortality remain uncertain at best. We estimated ship strike mortality for blue humpback and fin whales in U.S. West Coast waters using a novel application of a naval encounter model. Mortality estimates from the model were far higher than current minimum estimates derived from stranding records and are closer to extrapolations adjusted for detection probabilities of dead whales.

Baleen whales are gigantic obligate filter feeders that exploit aggregations of small-bodied prey in littoral, epipelagic, and mesopelagic ecosystems. At the extreme of maximum body size observed among mammals, baleen whales exhibit a unique combination of high overall energetic demands and low mass-specific metabolic rates. As a result, most baleen whale species have evolved filter-feeding mechanisms and foraging strategies that take advantage of seasonally abundant yet patchily and ephemerally distributed prey resources.

Individual ID mark-recapture studies are critical to our understanding of marine mammals, yet gathering, processing and identifying individuals in images remains exceptionally labor and cost intensive.

Muscle serves a wide variety of mechanical functions during animal feeding and locomotion, but the performance of this tissue is limited by how far it can be extended. In rorqual whales, feeding and locomotion are integrated in a dynamic process called lunge feeding, where an enormous volume of prey-laden water is engulfed into a capacious ventral oropharyngeal cavity that is bounded superficially by skeletal muscle and ventral groove blubber (VGB).

For marine animals, acoustic communication is critical for many life functions, yet individual calling behavior is poorly understood for most large whale species. Until recently, identifying the calling individual in a group of socializing baleen whales, through either passive acoustic monitoring or acoustic tagging methods, has been challenging because of inadequate spatial resolution in localization, and ambiguities in sound measurements recorded from animal-borne tags.

Multi-sensor archival tags have become a relatively common tool for studying the underwater behavior of diving animals, including whales. Rorqual whales (Balaenopteridae) feed via an energetically costly, complex behavior called lunge feeding, an intermittent ram filtration mechanism. This process includes kinematic maneuvers at depth and near the surface that have signatures evident in a number of tag sensors. The extreme size of rorqual species requires high energetic demands and consequently high feeding rates.

A joint project in February 2016 on and around the Pacific Missile Range Facility (PMRF) was carried out utilizing combined boat-based field efforts and passive acoustic monitoring from the Marine Mammal Monitoring on Navy Ranges (M3R) system. Five days of small boat effort were funded by the U.S. Navy and an additional two days of effort were funded by the National Marine Fisheries Service. There were 581 kilometers (36 hours [hr]) of small-vessel survey effort over the course of the seven‑day project.

Maneuverability is one of the most important and least understood aspects of animal locomotion. The hydrofoil-like flippers of cetaceans are thought to function as control surfaces that effect maneuvers, but quantitative tests of this hypothesis have been lacking. Here we construct a simple hydrodynamic model to predict the longitudinal-axis roll performance of fin whales, and we test its predictions against kinematic data recorded by onboard movement sensors from 27 free-swimming fin whales.