Faeces were collected from four captive harbour seals (Phoca vitulina) that consumed known amounts of herring (Clupea harengus), walleye pollock (Theragra chalcogramma), Pacific hake (Merluccius productus), surf smelt (Hypomesus pretiosus), and juvenile chinook salmon (Oncorhynchus tshawytscha). The goal was to determine which structures (hard parts) passed through the digestive tract (e.g., eye lenses, scales, vertebrae, otoliths), and which of these could be used to determine the type and number of fish consumed. Nearly 5000 fish were consumed, from which over 50 000 hard parts were recovered from seal faeces. Scales were the most numerous of the 23 structures recovered (>20 000), followed by vertebrae, eye lenses, and otoliths. Morphological distinctiveness and digestive erosion of the structures varied among fish taxa. Two to five structures accounted for over 90% of the taxon-specific elements recovered, depending upon the species of fish consumed. Otoliths, which are used routinely to characterize pinniped diets, accounted for only 17% of the identified taxon-specific hard parts. The variation in types of structures and rates of recovery across taxa underscores the importance of using several types of hard parts to identify prey. Identifying several different prey structures increases the likelihood of identifying a prey type.
Harbor seals (Phoca vitulina) are small pinnipeds that are widely distributed throughout the temperate coastal regions of the Atlantic and Pacific oceans. We determined birth mass, neonatal growth rates, weaning age, and weaning mass of NE Pacific harbor seals (P. v. richardsi) during a capture‐recapture study that spanned the nursing period (Sidney Island, British Columbia, Canada). Of 46 harbor seal pups initially captured, 28 were classified as newborns (i. e., < 24 h old). Mean body mass of newborns was 11.2 ± SE 0.31 kg. Pups were individually tagged and recaptured throughout the nursing period. Average daily mass gain during the nursing period was 394 ± 26 g. Mean birth mass of males did not differ significantly from females, although pups found with fetal pelage (lanugo) (21.4% of all newborns) were smaller at birth (9.8 ± 0.44 kg) than non‐lanugo pups (11.6 ± 0.33 kg). Mean weaning mass was estimated at 23.6 ± 1.2 kg at a mean weaning age of 32 d ± 1.5 d. While birth and weaning masses differed little from the published data for offshore Sable Island harbor seals (P. v. concolor), British Columbia harbor seals are characterized by half the daily mass gain and a longer nursing period.
Background/aimsDocumentation of conjunctival forniceal foreshortening in cases of progressive cicatrising conjunctivitis (PCC) is important in ascertaining disease stage and progression. Lower fornix shortening is often documented subjectively or semi-objectively, whereas upper forniceal obliteration is seldom quantified. Although tools such as fornix depth measurers (FDMs) have been described, their designs limit upper fornix measurement. The purpose of this study was to custom-design a FDM to evaluate the upper fornix and to assess variability in gauging fornix depth.MethodsA polymethylmethacrylate FDM was constructed using industry-standard jewellery computer software and machinery. Two observers undertook a prospective independent evaluation of central lower fornix depth in a heterogeneous cohort of patients with clinically normal and abnormal conjunctival fornices both subjectively and by using the FDM (in mm). Upper central fornix depth was also measured. Agreement was assessed using Bland–Altman plots.ResultsFifty-one eyes were evaluated. There was 100% intraobserver agreement to within 1 mm for each observer for lower fornix measurement. The mean difference in fornix depth loss using the FDM between observer 1 and 2 was 1.19%, with 95% confidence of agreement (±2SD) of −15% to +20%. In total, 86% (44/51) of measurements taken by the two observers agreed to within 10% of total lower fornix depth (ie, ±1 mm) versus only 63% (32/51) of the subjective measurements. Mean upper fornix difference was 0.57 mm, with 95% confidence of agreement of between −2 and +3 mm.ConclusionsThis custom-designed FDM is well tolerated by patients and shows low intraobserver and interobserver variability. This enables repeatable and reproducible measurement of upper and lower fornix depths, facilitating improved rates of detection and better monitoring of progression of conjunctival scarring.
Feces were collected from six Steller sea lions (Eumetopias jubatus) that consumed known amounts of Atka mackerel (Pleurogrammus monopterygius), Pacific herring (Clupea barengus), pink salmon (Oncorbyncbus gorbuscba), walleye pollock (Tberagra cbalcogramma), and squid (Loligo opalacens). The goal was to determine the numbers and types of taxon-specific hard parts that pass through the digestive tract and to develop correction factors for certain abundantly occurring structures. Over 20,000 fish and squid were consumed during 267 d of fecal collection. During this period, over 119,000 taxonspecific hard parts, representing 56 different structures, were recovered. Skeletal structures and non-skeletal structures accounted for 72% and 28% of all hard parts, respectively. The branchiocranium, axial skeleton, and dermocranium regions of the skeletal system accounted for the greatest number of hard parts recovered. Over 70% of all recovered hard parts were represented by one to six taxa specific structures for each prey type. The average number of hard parts (3.1-31.2) and structure types (2.0-17.7) recovered per individual prey varied across taxa and were used to derive correction factors (to reconstruct original prey numbers). A measure of the variability of hard part recovery among sea lions showed no difference for certain herring, pollock, and squid structures, however, there was a significant difference for salmon and Atka mackerel structures. Identifying all taxon-specific prey hard parts increases the likelihood of identifying and estimating the number of prey consumed.
Understanding health and mortality in killer whales (Orcinus orca) is crucial for management and conservation actions. We reviewed pathology reports from 53 animals that stranded in the eastern Pacific Ocean and Hawaii between 2004 and 2013 and used data from 35 animals that stranded from 2001 to 2017 to assess association with morphometrics, blubber thickness, body condition and cause of death. Of the 53 cases, cause of death was determined for 22 (42%) and nine additional animals demonstrated findings of significant importance for population health. Causes of calf mortalities included infectious disease, nutritional, and congenital malformations. Mortalities in sub-adults were due to trauma, malnutrition, and infectious disease and in adults due to bacterial infections, emaciation and blunt force trauma. Death related to human interaction was found in every age class. Important incidental findings included concurrent sarcocystosis and toxoplasmosis, uterine leiomyoma, vertebral periosteal proliferations, cookiecutter shark (Isistius sp.) bite wounds, excessive tooth wear and an ingested fish hook. Blubber thickness increased significantly with body length (all p < 0.001). In contrast, there was no relationship between body length and an index of body condition (BCI). BCI was higher in animals that died from trauma. This study establishes a baseline for understanding health, nutritional status and causes of mortality in stranded killer whales. Given the evidence of direct human interactions on all age classes, in order to be most successful recovery efforts should address the threat of human interactions, especially for small endangered groups of killer whales that occur in close proximity to large human populations, interact with recreational and commercial fishers and transit established shipping lanes.
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