False killer whale dorsal fin disfigurements as a possible indicator of long-line fishery interactions in Hawaiian Waters

Scarring resulting from entanglement in fishing gear can be used to examine cetacean fishery interactions. False killer whales (Pseudorca crassidens) are known to interact with the Hawai'i-based tuna and swordfish long-line fishery in offshore Hawaiian waters. We examined the rate of major dorsal fin disfigurements of false killer whales from nearshore waters around the main Hawaiian Islands to assess the likelihood that individuals around the main islands are part of the same population that interacts with the fishery. False killer whales were encountered on 11 occasions between 2000 and 2004, and 80 distinctive individuals were photographically documented. Three of these (3.75%) had major dorsal fin disfigurements (two with the fins completely bent over and one missing the fin). Information from other research suggests that the rate of such disfigurements for our study population may be more than four times greater than for other odontocete populations. We suggest that the most likely cause of such disfigurements is interactions with longlines and that false killer whales found in nearshore waters around the main Hawaiian Islands are part of the same population that interacts with the fishery. Two of the animals documented with disfigurements had infants in close attendance and were thought to be adult females. This implies that even with such injuries, at least some females may be able to produce offspring, despite the importance of the dorsal fin in reproductive thermoregulation

Movements and spatial use of odontocetes in the western main Hawaiian Islands: results from satellite-tagging and photo-identification off Kaua‘i and Ni‘ihau in July/August 2011

Although considerable information is available on residency patterns and spatial use of odontocetes in the eastern half of the Hawai‘i Range Complex (HRC), much less is known about odontocetes in the western half of the HRC. In the second year of a three-year effort in the western main Hawaiian Islands we undertook surveys off Kaua‘i and Ni‘ihau in July/August 2011, to examine spatial use and residency patterns using satellite tags, to provide visual verification of acoustically-detected odontocetes on the Pacific Missile Range Facility (PMRF), and to obtain individual identification photographs and biopsy samples for assessment of population identity and structure. During 18 days of field effort we covered 1,972 km of trackline and had 65 encounters with five species of odontocetes. Twenty-four of the encounters, of three species, were cued by acoustic detections from the Marine Mammal Monitoring on Navy Ranges (M3R) system, thus providing species verifications for future use of the M3R system on the PMRF range. During the 65 encounters we obtained 22,645 photos for individual and species identification, and collected 48 biopsy samples for genetic analyses. One encounter with a group of four killer whales was only the second encounter with this species in 12 years of directed field surveys in Hawaiian waters. Photos from that encounter were compared to our photo-identification catalog but no matches were found, further suggesting that there is no population of this species resident to the Hawaiian Islands. There were three encounters with a lone pantropical spotted dolphin, each time in association with a group of spinner dolphins. Photos of this individual matched to a spotted dolphin identified off Kaua‘i in 2004 and in 2005, both times with spinner dolphins, suggesting this individual may be part of a long-term association with spinner dolphins. Four satellite tags were deployed; three on rough-toothed dolphins and one on a bottlenose dolphin. These are the first tag deployments on either species in Hawaiian waters and the first deployments of satellite tags on free-ranging rough-toothed dolphins anywhere in the world. Rough-toothed dolphin tag data were obtained over periods from 7.6 to 18.5 days. Over these periods the three rough-toothed dolphins moved cumulative horizontal distances ranging from 573 to 1,295 km, yet remained an average distance from the tagging locations of from 10.4 to 13.9 km. Median depths used by the three rough-toothed dolphins ranged from 816 to 1,107 m, with median distance from shore ranging from 11.6 to 12.2 km. Two of the three individuals had been previously photo-identified off Kaua‘i (in 2007 or 2008), and all link by association with the resident population from Kaua‘i and Ni‘ihau. Movement and habitat use data were obtained over a 34-day period for the satellite-tagged bottlenose dolphin. During this time the individual remained associated with the island of Kaua‘i using waters with a median depth of 82 m. Although this individual had not been previously photo-identified, others from the group it was in had been previously documented off Kaua‘i and/or Ni‘ihau in 2003-2005, suggesting it is part of the island-resident population. Overall these efforts provide the first unbiased movement and habitat use data for both species in Hawaiian waters.Grant No. N00244-10-1-004

A SURVEY FOR ODONTOCETE CETACEANS OFF KAUA‘I AND NI‘IHAU, HAWAI‘I, DURING OCTOBER AND NOVEMBER 2005: EVIDENCE FOR POPULATION STRUCTURE AND SITE FIDELITY

Considerable uncertainty exists regarding population structure and population sizes of most species of odontocetes in the Hawaiian Islands. A small-boat based survey for odontocetes was undertaken off the islands of Kaua‘i and Ni‘ihau in October and November 2005 to photoidentify individuals and collect genetic samples for examining stock structure. Field effort on 24 days covered 2,194 km of trackline. Survey coverage was from shallow coastal waters out to over 3,000 m depth, though almost half (47%) was in waters less than 500 m in depth. There were 56 sightings of five species of odontocetes: spinner dolphins (30 sightings); bottlenose dolphins (14 sightings); short-finned pilot whales (6 sightings); rough-toothed dolphins (5 sightings); and pantropical spotted dolphins (1 sighting). One hundred and five biopsy samples were collected and 14,960 photographs were taken to document morphology and for individual photo-identification. Photographs of distinctive individuals of three species (bottlenose dolphins, 76 identifications; rough-toothed dolphins, 157 identifications; short-finned pilot whales, 68 identifications) were compared to catalogs of these species from a survey off Kaua‘i and Ni‘ihau in 2003, as well as from efforts off O‘ahu, Maui/Lana‘i and the island of Hawai‘i. Within- and between-year matches were found for all three species with individuals previously identified off Kaua‘i and Ni‘ihau, though no matches were found with individuals off any of the other islands. This suggests site fidelity to specific island areas, and population structure among island areas for all three species. Movements of photographically identified bottlenose dolphins were documented between deep water areas off the islands of Kaua‘i and Ni‘ihau, as well as between shallow (\u3c350 m) and deep (\u3e350 m) waters. A lack of sightings or reports of false killer whales off Kaua‘i or Ni‘ihau during our study, combined with documented movements among the other main Hawaiian Islands, suggest that there is no “resident” population of false killer whales that inhabits waters only off Kaua‘i or Ni‘iha

Range and primary habitats of Hawaiian insular false killer whales: informing determination of critical habitat

The article of record as published may be found at https://dx.doi.org/10.3354/esr00435For species listed under the US Endangered Species Act, federal agencies must designate 'critical habitat', areas containing features essential to conservation and/or that may require special management considerations. In November 2010, the National Marine Fisheries Service proposed listing a small demographically isolated population of false killer whales Pseudorca crassidens in Hawai'i as endangered but has not yet proposed designating critical habitat. We assessed the population's range and heavily used habitat areas using data from 27 satellite tag deployments. Assessment of independence of individuals with temporally overlapping data indicated that data were from 22 'groups'. Further analyses were restricted to 1 individual per group. Tag data were available for periods of between 13 and 105 d (median = 40.5 d), with 8513 locations (93.4% from July-January). Analyses of photo-identification data indicated that the population is divided into 3 large associations of individuals (social clusters), with tag data from 2 of these clusters. Ranges for these 2 clusters were similar, although one used significantly deeper waters, and their high-use areas differed. A minimum convex polygon range encompassing all locations was ~82800 km2, with individuals ranging from Ni'ihau to Hawai'i Island and up to 122 km offshore. Three high-use areas were identified: (1) off the north half of Hawai'i Island, (2) north of Maui and Moloka'i and (3) southwest of Lana'i. Although this analysis provides information useful for decision-making concerning designation of critical habitat, there are likely other high-use areas that have not yet been identified due to seasonal limitations and availability of data from only 2 of the 3 main social clusters.Fieldwork was primarily funded by grants and contracts to Cascadia Research Collective from the National Marine Fisheries Service Pacific Islands Fisheries Science Center and the US Navy (N45) through the Southwest Fisheries Science Center, Woods Hole Oceano- graphic Institution, and the Naval Postgraduate School. The Wild Whale Research Foundation and Dolphin Quest provided additional support.Funded by Naval Postgraduate School.Office of Naval Research Grant N00014081120

Defining bottlenose dolphin (\u3ci\u3eTursiops truncatus\u3c/i\u3e) stocks based on environmental, physical, and behavioral characteristics

The population structure of bottlenose dolphins, Tursiops truncatus, along the U.S. Atlantic coast has recently been redefined from one homogenous population into five coastal stocks. Local studies indicate even finer structure, primarily based on isolation of dolphins inhabiting estuaries.We identified population structuring of non-estuarine coastal bottlenose dolphins during a study in New Jersey, the northern range along the Atlantic Coast. Using photo-identification and distribution survey results, an analysis identified two major clusters of individuals significantly separated by five variables (distance from shoreline, group size, occurrence of the barnacle Xenobalanus globicipitis, avoidance behavior, and individual coloration). Sightings assigned to cluster 1 occurred in nearshore shallow waters (0–1.9 km, avg x = 3.5 m), and those assigned to cluster 2 occurred further offshore in deeper waters (1.9–6 km, avg x = 9.5 m). Only eight of 194 individuals (4%) were identified in both regions. Collectively, this suggests an occurrence of two stocks that are spatially, physically, and behaviorally distinguishable over a small distance. These results indicate that complexity in Tursiops population structure is not limited to latitudinal gradients or barriers created by estuarine habitats, but also by partitioning of habitat as a function of distance from shore and depth over small distances

Movements and Spatial Use of Odontocetes in the Western Main Hawaiian Islands: Results from Satellite-Tagging and Photo-Identification off Kaua'i and Ni'ihau in July/August 2011.

This report summarizes the second year of a three-year effort in the western main Hawaiian Islands to study the residency patterns and spatial use of odontocetes in the Hawaii Range Complex. Surveys were made off Kaua‘i and Ni‘ihau over eighteen days in July/August 2011, during which time there were 65 encounters with five species of odontocetes. Twenty-four of those encounters were cued by acoustic detections from the Marine Mammal Monitoring on Navy Ranges (M3R) system from the Pacific Missile Range Facility, thus providing species verifications of the acoustic system. Additionally, 22645 photographs for individual and species identification, and forty-eight biopsy samples for genetic analyses, were collected. Some highlights of the field work include: the first ever satellite tag deployments on free-ranging rough-toothed dolphins, and the first satellite tag deployment in Hawaiian waters of a bottlenose dolphin; only the second encounter with killer whales in twelve years of surveys in Hawaiian waters; and encounters with a lone pantropical spotted dolphin, always in association with a group of spinner dolphins, as has been similarly documented in 2004 and 2005. The latter two highlights suggest, respectively, that there is no resident Hawaiian killer whale population, and that this particular (at least) pantropical spotted dolphin has a long-term association with spinner dolphins. The first highlight has provided the first unbiased movement and habitat use data for both rough-toothed and bottlenose dolphins in Hawaiian waters.N00244-10-1-004

Movement and spatial use of Odontocetes in the western main Hawaiian Islands: results of a three-year study off O'ahu and Kaua'i

Work was carried out by Cascadia Research Collective, Olympia, Washington 98501Understanding the impacts of anthropogenic activities on animal populations requires knowledge of their population structure, sizes and ranges. In Hawaiian waters this type of basic information has been lacking or is restricted to areas where conditions have been more favorable to research efforts, namely the eastern main Hawaiian Islands. As part of an effort to reduce uncertainty regarding the population, range and abundance of odontocetes in the western main Hawaiian Islands, and to help inform Navy impact assessments, we undertook small-boat based research efforts off O'ahu (2010) and Kaua'i (2011 & 2012). A variety of field methods were used, including photo-identification, collection of biopsy samples for genetic studies, and satellite tagging. There were 191 odontocete sightings, 183 identified to species. 102 biopsy samples were collected from 7 species. 30 satellite tags were deployed on 5 species: pygmy and false killer whales, bottlenose and rough-toothed dolphins, and short finned pilot whales. Our efforts substantially increased what is known in particular about the movements and habitat use of these 5 species of odontocetes in the western main Hawaiian Islands.CNO (N45) (N00244-10-1-0048

A SURVEY FOR ODONTOCETE CETACEANS OFF KAUA‘I AND NI‘IHAU, HAWAI‘I, DURING OCTOBER AND NOVEMBER 2005: EVIDENCE FOR POPULATION STRUCTURE AND SITE FIDELITY

Considerable uncertainty exists regarding population structure and population sizes of most species of odontocetes in the Hawaiian Islands. A small-boat based survey for odontocetes was undertaken off the islands of Kaua‘i and Ni‘ihau in October and November 2005 to photoidentify individuals and collect genetic samples for examining stock structure. Field effort on 24 days covered 2,194 km of trackline. Survey coverage was from shallow coastal waters out to over 3,000 m depth, though almost half (47%) was in waters less than 500 m in depth. There were 56 sightings of five species of odontocetes: spinner dolphins (30 sightings); bottlenose dolphins (14 sightings); short-finned pilot whales (6 sightings); rough-toothed dolphins (5 sightings); and pantropical spotted dolphins (1 sighting). One hundred and five biopsy samples were collected and 14,960 photographs were taken to document morphology and for individual photo-identification. Photographs of distinctive individuals of three species (bottlenose dolphins, 76 identifications; rough-toothed dolphins, 157 identifications; short-finned pilot whales, 68 identifications) were compared to catalogs of these species from a survey off Kaua‘i and Ni‘ihau in 2003, as well as from efforts off O‘ahu, Maui/Lana‘i and the island of Hawai‘i. Within- and between-year matches were found for all three species with individuals previously identified off Kaua‘i and Ni‘ihau, though no matches were found with individuals off any of the other islands. This suggests site fidelity to specific island areas, and population structure among island areas for all three species. Movements of photographically identified bottlenose dolphins were documented between deep water areas off the islands of Kaua‘i and Ni‘ihau, as well as between shallow (\u3c350 m) and deep (\u3e350 m) waters. A lack of sightings or reports of false killer whales off Kaua‘i or Ni‘ihau during our study, combined with documented movements among the other main Hawaiian Islands, suggest that there is no “resident” population of false killer whales that inhabits waters only off Kaua‘i or Ni‘iha

Patterns of association and distribution of estuarine-resident common bottlenose dolphins (Tursiops truncatus) in North Carolina, USA

The social structure of estuarine-resident bottlenose dolphins is complex and varied. Residing in habitats often utilized for resource exploitation, dolphins are at risk due to anthropogenic pressures while still federally protected. Effective conservation is predicated upon accurate abundance estimates. In North Carolina, two estuarine-resident stocks (demographically independent groups) of common bottlenose dolphin have been designated using spatiotemporal criteria. Both stocks are subjected to bycatch in fishing gear. The southern North Carolina estuarine stock was estimated at <200 individuals from surveys in 2006, which is outdated per US guidelines. Thus, we conducted a new capture-mark-recapture survey in 2018, identifying 547 distinct individuals, about three times higher than the prior abundance estimate. We compared those individuals to our long-term photo-identification catalog (1995-2018, n = 2,423 individuals), matching 228 individuals. Of those 228, 65 were also included in the 2013 abundance estimate for the northern North Carolina estuarine stock. Using sighting histories for all individuals in the long-term catalog, we conducted a social network analysis, which is independent of a priori stock assignments. The three primary clusters identified were inconsistent with current stock designations and not defined by spatiotemporal distribution. All three clusters had sighting histories in the estuary and on the coast, however, that with the highest within-cluster associations appeared to use estuarine waters more often. The within-cluster association strength was low for one cluster, possibly due to only part of that cluster inhabiting the southern North Carolina estuarine system. Between-cluster differences occurred in infestation rates by the pseudostalked barnacle, Xenobalanus globicipitis, but that did not predict clusters. We suggest the need to re-evaluate the stock structure of estuarine-resident common bottlenose dolphins in North Carolina and currently have insufficient information to assign an abundance estimate to a currently designated stock

Movements and Spatial Use of Odontocetes in the Western Main Hawaiian Islands: Results from Satellite-Tagging and Photo-Identification off Kaua'i and Ni'ihau in July/August 2011.

Annual progress report under Grant No. N00244-10-1-0048 from the Naval Postgraduate SchoolThis report summarizes the second year of a three-year effort in the western main Hawaiian Islands to study the residency patterns and spatial use of odontocetes in the Hawaii Range Complex. Surveys were made off Kaua i and Ni ihau over eighteen days in July/August 2011, during which time there were 65 encounters with five species of odontocetes. Twenty-four of those encounters were cued by acoustic detections from the Marine Mammal Monitoring on Navy Ranges (M3R) system from the Pacific Missile Range Facility, thus providing species verifications of the acoustic system. Additionally, 22645 photographs for individual and species identification, and forty-eight biopsy samples for genetic analyses, were collected. Some highlights of the field work include: the first ever satellite tag deployments on free-ranging rough-toothed dolphins, and the first satellite tag deployment in Hawaiian waters of a bottlenose dolphin; only the second encounter with killer whales in twelve years of surveys in Hawaiian waters; and encounters with a lone pantropical spotted dolphin, always in association with a group of spinner dolphins, as has been similarly documented in 2004 and 2005. The latter two highlights suggest, respectively, that there is no resident Hawaiian killer whale population, and that this particular (at least) pantropical spotted dolphin has a long-term association with spinner dolphins. The first highlight has provided the first unbiased movement and habitat use data for both rough-toothed and bottlenose dolphins in Hawaiian waters.Naval Postgraduate SchoolGrant No. N00244-10-1-004