Melanomacrophages in three species of free‐ranging sharks from the northwestern Atlantic, the blue shark Prionacae glauca (L.), the shortfin mako, Isurus oxyrhinchus Rafinesque, and the thresher, Alopias vulpinus (Bonnaterre)

Abstract

The melanomacrophage aggregates or cells (MMC) are commonly used as biomarkers of exposure to pollution in fish, albeit their numbers and morphological characteristics can be influenced not only by environmental toxins but also by a range of physiological parameters and pathological conditions. Accordingly, before we can use MMC as biomarkers in any fish species, their normal, 'background' characteristics have to be established in apparently healthy fish. The knowledge of MMC in sharks is minimal. The aim of this study was to characterize MMC from 51 free-ranging, large pelagic sharks from the northwestern Atlantic, including shortfin mako, Isurus oxyrhinchus, thresher, Alopias vulpinus and blue shark, Prionacae glauca. The rationale of this study was twofold. First, because, sharks have life histories predisposing them to the accumulation of environmental toxins they constitute good sentinel species of the health of the global marine ecosystem. Second, because many shark populations are in decline or threatened by extinction, we need to expand our understanding of their health status in order to develop appropriate protective measures. All sharks were collected by sports fishing gear between June and August in 2007. Their health condition was assessed by necropsy, morphometrics, and by microscopic examination of gonads, livers, spleens and kidneys. Routine, haematoxylin and eosin and/or Pearl's reagent-stained paraffin embedded sections were studied by light microscopy. Our results provide the first data on the morphometric and morphological characteristics of MMC in viscera of apparently healthy free-ranging sharks from the northwestern Atlantic.

Effects of Biodegradable Detergents in the Accumulation of Lipofuscin (Age Pigment) in Gill and Liver of Two Neotropical Fish Species

“…Quite a few researchers demonstrate effects of contamination on lipofuscin accumulation, such as Vaschenco et al (2012), who showed that pollutants as well as anoxic environments, affect lipofuscin accumulation in mollusks; and Banni et al (2009), who demonstrated that lipofuscin naturally accumulates with age in mollusks, but that the process can be accelerated by pollutants. Similar results can be found in studies by Radwan et al (2010), Borucinska et al (2009), Han & Fang (2010), Machella et al, (2005) and Teh et al (1997), for Thebapisana, Prionacae glauca, Xiphophorus helleri, Anguilla Anguilla and Lepomisauritu, respectively.…”

Mortality due to a retained circle hook in a longfin mako shark Isurus paucus (Guitart‐Manday)

“…Both of these parameters can vary widely depending on species, gender and life history stage, and thus, our comparisons with data collected from different shark species and different life histories provide only a rough comparison (Borucinska et al . ; Borucinska & Adams ; unpublished data).…”

The Iconic Atlantic Goliath Grouper (Epinephelus itajara): A Comprehensive Assessment of Health Indices in the Southeastern United States Population

“…For each prepared microscope slide, five images were taken of random and non-overlapping representative areas at each 100× and 400× total magnification. Counts of PMAs were quantified manually from 100× images, and area of PMA per total image area in pixels and percent area occupied by PMAs were calculated ( 42 ) from 400× images using ImageJ software ( 43 ). The five counts and area estimates were then averaged per slide and reported as PMA % area and count ( 44 ).…”