Victoria Bendall

Concentrations of mercury and other trace elements in porbeagle shark Lamna nasus.

Concentrations of 11 trace elements in three tissues of porbeagle shark Lamna nasus (n=33) were determined. The maximum observed concentrations of Cd and Pb in muscle were 0.04 and 0.01mgkg-1, respectively, and all muscle samples were below European seafood limits for these metals. Hg concentrations in either the red or white muscle that exceeded European regulations for seafood were observed in one-third of specimens. Hg concentration, however, increased with length, and all fish >195cm had concentrations >1.0mgkg-1, with a maximum observed value of 2.0mgkg-1. Concentrations of Fe and Cu were, on average, 9.7 and 10 times higher in red muscle than in nearby white muscle, respectively. Mn, Zn, As and Se were also found in significantly higher concentrations in red muscle than in white muscle.

Effects of Pile Driving on the Behavior of Cod and Sole

Studies on the effects of offshore wind farm construction on marine life have focused on behavioral reactions in porpoises and seals (Thomsen et al. 2006). The effects on fish have only very recently come into the focus of scientists, regulators, and stakeholders (Popper and Hastings 2009). Pile-driving noise during construction is of particular concern because the very high sound pressure levels (see Thomsen et al. 2006) could potentially prevent fish from reaching breeding or spawning sites, finding food, and acoustically locating mates that could result in long-term effects on reproduction and population parameters. There is also the possibility that avoidance reactions might displace fish away from potential fishing grounds that could lead to reduced catches (see, e.g., Engas et al. 1996). However, the nature and extent of behavioral reactions of marine fish due to pile driving have not been studied in controlled experiments. Therefore, the impacts of pile driving on marine fish remain unknown.

A Novel Field Study Setup to Investigate the Behavior of Fish Related to Sound

There is an urgent need to obtain information on the effects of underwater sound on marine fish due to imminent policy drivers, e.g., the European Union Marine Strategy Framework Directive, on one hand and the increasingly noisy activities in the marine environment on the other. Yet studying the influence of sound, particularly on the behavior of fish, is a challenging task. Studies in tanks can suffer problems with the reflection of sound, especially at the low frequencies that are most important for fish. Studies in the field are often limited because the observation of fish is very complicated.

Behavioral reactions of cod and sole to playback of pile driving sound.

The effect of anthropogenic underwater sound on fish has become an important environmental issue. Pile‐driving noise during construction is of particular concern as the very high sound pressure levels could potentially prevent fish from reaching breeding or spawning sites, finding food, and acoustically locating mates. This could result in long‐term effects on reproduction and populationparameters. Additionally, avoidance reactions might result in displacement away from potential fishing grounds and lead to reduced catches. However, reaction thresholds and therefore the impacts of pile driving on the behavior of fish are completely unknown. Pile‐driving noise was played back to cod and sole held in two large (40 m) net pens located in a quiet bay. Movements of the fish were analyzed using a novel acoustic tracking system. Received sound pressure level and particle motion were measured during the experiments. The results show significant movement responses to the pile‐driving stimulus in both species at re...

Teleost and elasmobranch eye lenses as a target for life-history stable isotope analyses

Incrementally grown, metabolically inert tissues such as fish otoliths provide biochemical records that can used to infer behavior and physiology throughout the lifetime of the individual. Organic tissues are particularly useful as the stable isotope composition of the organic component can provide information about diet, trophic level and location. Unfortunately, inert, incrementally grown organic tissues are relatively uncommon. The vertebrate eye lens, however, is formed via sequential deposition of protein-filled fiber cells, which are subsequently metabolically inert. Lenses therefore have the potential to serve as biochemical data recorders capturing life-long variations in dietary and spatial ecology. Here we review the state of knowledge regarding the structure and formation of fish eye lenses in the context of using lens tissue for retrospective isotopic analysis. We discuss the relationship between eye lens diameter and body size, describe the successful recovery of expected isotopic gradients throughout ontogeny and between species, and quantify the isotopic offset between lens protein and white muscle tissue. We show that fish eye lens protein is an attractive host for recovery of stable isotope life histories, particularly for juvenile life stages, and especially in elasmobranchs lacking otoliths, but interpretation of lens-based records is complicated by species-specific uncertainties associated with lens growth rates.