Cetaceans as Ocean Health Indicators of Marine Litter Impact at Global Scale

Fossi, María Cristina; Baini, Matteo; Simmonds, Mark

doi:10.3389/fenvs.2020.586627

Cited by 38 publications

(16 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These changes can lead to lower prey availability for marine mammal populations, resulting in poorer health and condition (Simmonds & Isaac, 2007). Marine mammals are top predators of the marine food web and are increasingly being recognized as important indicators for ocean health (Fossi et al, 2020; Plön et al, 2021). Using body condition as a sentinel parameter to monitor ecosystem health, recent studies have used the adipocyte index (AI) obtained from biopsy samples of live humpback whales ( Megaptera novaeangliae ; Castrillon et al, 2017) as a rapid, nonlethal and low‐cost method to monitor body condition.…”

Section: Discussionmentioning

confidence: 99%

Histomorphological stratification of blubber of three dolphin species from subtropical waters

Roussouw

Vliet

Naidoo³

et al. 2022

Journal of Morphology

View full text Add to dashboard Cite

Blubber is a highly specialized and dynamic tissue unique to marine mammals and presents a reflection of the individuals' nutrition, environment, and life history traits.Few studies have investigated the histomorphology of cetacean blubber in subtropical environments. The aim of this study was to investigate the blubber histomorphology of three different dolphin species off the subtropical KwaZulu-Natal coast, South Africa, using adipocyte cell size, number, and density. Blubber tissue samples from the saddle area of 43 incidentally bycaught animals (four Sousa plumbea, 36 Tursiops aduncus, and three Delphinus delphis) were used to compare cell parameters between blubber layers. Samples were divided into the upper third (corresponding to the superficial layer closest to the epidermis), middle third, and lower third (corresponding to the deep layer). For T. aduncus, factors potentially affecting blubber histomorphology, such as sex, age class, and season, were also assessed. Our results showed that no stratification was present in S. plumbea, which could be ascribed to the species' warmer inshore habitat, large body size, and apparent lower mobility. For T. aduncus and D. capensis, however, blubber stratification was determined, characterized by a gradual transition of cell size, number, and density between layers rather than clearly defined layers. Significant differences in adipocyte cell number and density were found for different sexes and age classes of T. aduncus. However, there were no significant differences between seasons, which was attributed to the small temperature differences between seasons. This study represents the first investigation of odontocete blubber histomorphology in subtropical waters. It is recommended that future studies investigate blubber lipid content, while also taking into consideration the reproductive status of the females and the temperature range of their study area.It is hoped that our results, in conjunction with histopathology and other health indicators, could assist in assessing health and body condition.

show abstract

Section: Discussionmentioning

confidence: 99%

Histomorphological stratification of blubber of three dolphin species from subtropical waters

Roussouw

Vliet

Naidoo³

et al. 2022

Journal of Morphology

View full text Add to dashboard Cite

show abstract

“…The mass of individual microplastics is governed by factors including size, morphology, and chemical composition of the microplastic. As a result, the range of microplastic weights spans a twentyfold range, from 0.23 mg to 4 mg per microplastic piece 18,53 . Using this range, we estimate a blue whale would consume 2.51 to 43.6 kg of microplastics per day.…”

Section: Resultsmentioning

confidence: 99%

Field measurements reveal exposure risk to microplastic ingestion by filter-feeding megafauna

et al. 2022

View full text Add to dashboard Cite

Microparticles, such as microplastics and microfibers, are ubiquitous in marine food webs. Filter-feeding megafauna may be at extreme risk of exposure to microplastics, but neither the amount nor pathway of microplastic ingestion are well understood. Here, we combine depth-integrated microplastic data from the California Current Ecosystem with high-resolution foraging measurements from 191 tag deployments on blue, fin, and humpback whales to quantify plastic ingestion rates and routes of exposure. We find that baleen whales predominantly feed at depths of 50–250 m, coinciding with the highest measured microplastic concentrations in the pelagic ecosystem. Nearly all (99%) microplastic ingestion is predicted to occur via trophic transfer. We predict that fish-feeding whales are less exposed to microplastic ingestion than krill-feeding whales. Per day, a krill-obligate blue whale may ingest 10 million pieces of microplastic, while a fish-feeding humpback whale likely ingests 200,000 pieces of microplastic. For species struggling to recover from historical whaling alongside other anthropogenic pressures, our findings suggest that the cumulative impacts of multiple stressors require further attention.

show abstract

“…Cetaceans can be killed by plastic ingestion because of gastric impaction and perforation or as a result of the associated lesions [ 66 ]. In only one case, the cause of death was presumed to be stomach perforation and obstruction caused by a large plastic bag and plastic packing straps.…”

Section: Discussionmentioning

confidence: 99%

Evaluating the Presence of Marine Litter in Cetaceans Stranded in the Balearic Islands (Western Mediterranean Sea)

Solomando

Pujol

Sureda

et al. 2022

Biology

View full text Add to dashboard Cite

The global distribution and presence of plastic, at all levels of the water column, has made plastic debris one of today’s greatest environmental challenges. The ingestion and entanglement of plastic-containing marine debris has been documented in more than 60% of all cetacean species. In light of the increasing pressure on cetaceans, and the diversity of factors that they face, the aim of this work is to provide evidence of the impact of plastic debris on stranded cetaceans, in terms of ingestion and entanglement, in the Balearic Islands for the first-time. Detailed examinations, necropsies, and plastic debris analysis were performed on 30 of the 108 cetaceans stranded between 2019 and 2022. Specimens belonging to five different species, Stenella coeruleoalba, Tursiops truncatus, Grampus griseus, Balaenoptera physalus, and Physeter macrocephalus, were evaluated. Ten percent of the cetaceans (N = 3) presented plastic debris in their stomach, with one case of obstruction and perforation. Fishery gear fragments (ropes and nets) were found in two adults of T. truncatus, whereas packaging debris (plastic bag, packing straps, and plastic sheets) were found in a juvenile P. macrocephalus. Plastic items analysed by Fourier transform infrared spectroscopy (FT-IR) reported three polymer types: polypropylene, polyamide, and high-density polypropylene. A total of seven cases of entanglement were recorded during the study, affecting four different species (S. coeruleoalba, T. truncatus, P. macrocephalus, and Megaptera novaeangliae). Only two individuals were freed from the nets, although one died after a week, whereas the rest were already found dead. In conclusion, data collected in the present study provided evidence of plastic ingestion and entanglement in cetaceans of the Balearic Islands for the first-time, thus highlighting the need for the regular examination of stranded cetaceans (as they are top predators) in future research to better understand the effects of these pollutants.

show abstract

Cetaceans as Ocean Health Indicators of Marine Litter Impact at Global Scale

Cited by 38 publications

References 37 publications

Histomorphological stratification of blubber of three dolphin species from subtropical waters

Histomorphological stratification of blubber of three dolphin species from subtropical waters

Field measurements reveal exposure risk to microplastic ingestion by filter-feeding megafauna

Evaluating the Presence of Marine Litter in Cetaceans Stranded in the Balearic Islands (Western Mediterranean Sea)

Contact Info

Product

Resources

About