Deep reef fish surveys by submersible on Alderdice, McGrail, and Sonnier Banks in the Northwestern Gulf of Mexico

Submersible surveys at numerous reefs and banks in the northwestern Gulf of Mexico (NWGOM) were conducted as part of the Sustainable Seas Expedition (SSE) during July/August 2002 to identify reef fish communities, characterize benthic habitats, and identify deep coral reef ecosystems. To identify the spatial extent of hard bottom reef communities, the Flower Garden Banks National Marine Sanctuary (FGBNMS) and the U.S. Geological Survey (USGS) mapped approximately 2000 km2 of the Northwestern Gulf of Mexico (NWGOM) continental shelf during June 2002 with high-resolution multibeam bathymetry. Previous investigations conducted on the features of interest (with the exceptions of East and West Flower Garden and Sonnier Banks, accessible by SCUBA) had not been conducted since the 1970s and 1980s, and did not have the use of high-resolution maps to target survey sites. The base maps were instrumental in navigating submersibles to specific features at each study site during the Sustainable Seas Expedition (SSE)—a submersible effort culminating from a partnership between the National Atmospheric and Oceanic Administration (NOAA) and the National Geographic Society (NGS). We report the initial findings of our submersible surveys, including habitat and reef fish diversity at McGrail, Alderdice, and Sonnier Banks. A total of 120 species and 40,724 individuals were identified from video surveys at the three banks. Planktivorous fishes constituted over 87% by number for the three banks, ranging from 81.4% at Sonnier Banks to 94.3% at Alderdice Bank, indicating a direct link to pelagic prey communities, particularly in the deep reef zones. High numbers of groupers, snappers, jacks, and other fishery species were observed on all three features. These sites were nominated as Habitat Areas of Particular Concern (HAPC) by the Gulf of Mexico Fishery Council in March 2004. Data obtained during this project will contribute to benthic habitat characterization and assessment of the associated fish communities through future SCUBA, ROV, and submersible missions, and allow comparisons to other deep reef ecosystems found throughout the Gulf of Mexico and western Atlantic Ocean.

Entwicklung einer einfachen und schnellen Analysenmethode für Kohlenmonoxid in Fisch – Teil 2: Methodenoptimierung

After having described in our first paper (Haase et al. 2005) the main features of an easy and fast method for determination of carbon monoxide in fish and the equipment and chemicals necessary as well as first results measured on fish samples, this part deals with the influence of sample preparation, variation of the size of samples, type of solvent, duration of extraction and further conditions on the result of analyses. Both variants of the method are evaluated with regard to measuring expected errors. The single components of the equipment, including prises, are listed to allow a reliable assessment of costs. Additional instrumental colour and DSC measurements on both untreated and CO-treated tuna illustrate the effects.

Veränderungen sensorischer und instrumenteller Parameter während der Gefrierlagerung von Ostseedorsch (Gadus morhua) bei unterschiedlichen Temperaturen

Changes in sensory and instrumental quality parameter sand in thawing drip, cooking drip and total drip loss of frozen stored Baltic cod fillets (Gadus morhua) at different storage temperatures were investigated. Cod fillets stored at –20 °C and –30 °C exhibited the lowest drip losses and obtained the highest sensory scores. Drip losses were found to be highest in cod fillets stored at –10°C and in double frozen fillets stored at –20 °C. These two experiments also gave the lowest sensory scores. The texture parameters increased during storage parallel with storage time. The waterbinding capacity was lowest at –10 °C and almost constant at –30 °C. There is a good correlation between the sensory scores for “tough” and the instrumental texture measurement for hardness and chewiness.

Spezifizierungsanalyse des Quecksilbers - ein möglicher Beitrag zur Erforschung der Auswirkungen klimatischer Veränderungen auf die belebte Meeresumwelt

The predominantly occurring chemical forms (species) of mercury (Hg) that occur in the environment are elemental mercury (Hg0), divalent inorganic mercury (Hg2+) and dimethylmercury (CH3HgCH3) and monomethylmercury(CH+3Hg), the latter of which is strongly accumulated by marine organisms. Conversions between the different mercury species provide the basis of the complex distribution pattern of mercury on local, regional, and global scales. An analytical system using hyphenated instrumental techniques has been developed and validated in order to determine inorganic and organic mercury species in marine biota (fish and plankton). It is suggested than mercury species analysis can provide a useful tool to investigate the effects of climate changes on the bio-transformation activity of certain marine microorganisms.

Qualitätsvergleich zwischen panierten Filetportionen aus einfach- und doppelgefrorenen TK-Blöcken

Single and double frozen fillet blocks of Alaska pollack and cod both commercially processed of unknown shelf life were further processed to breaded battered portions. The quality of these fillet portions were compared using sensory (QDA), physical and chemical methods. It was difficult to differentiate between SF and DF fillets by sensory method because of the absence of differences in flavour attributes. While no differences could to be found in the texture of cod fillets, in Alaska pollack fillets some texture attributes were significantly different. These differences could not be verified by instrumental texture measurement. In all cases the lightness was different between SF and DF fillets. Probably, after having fixed L* values for SF fillets of commercially important fish species as limit this could be employed in the future to differentiate between single and double frozen products. Due to the unknown shelf life it is difficult to evaluate the results. Therefore, the investigation of the influence of double freezing on the quality needs a special sample preparation. The use of randomly taken commercially processed samples seems not to be useful.

Vergleichende Texturuntersuchungen an Filets von Kliesche (Limanda limanda) und Scholle (Pleuronectes platessa) in Abhängigkeit von Eislagerzeit post mortem, TK-Lagerung und Erhitzen

Instrumental investigations of texture have been performed using texture profile analysis. The following textural parameters have been assessed: hardness, gumminess, chewiness, springiness, cohesiveness and adhesiveness. The fillets of both species have been prepared from deep frozen headed and gutted raw material without fins after frozen storage of 0, 23 and 34 weeks, respectively. Deep freezing of fishes has been performed on board immediately after hauling or after 6 day’s storage in ice. Before texture measurement the raw material has been thawed and the measurement was carriedout on both thawed and microwave-heated fillets. In general, it can be concluded that both fish species are comparable in their texture parameters. The hardness of heated dab has been slightly higher comparing with that one of plaice. All other texture parameters showed a fairly good conformity between both species. While the hardness of dab increased during heating, it was decreasing in plaice. This was the only one significant difference between both fishes during heating. Adhesiveness as well as cohesiveness increased remarkably during heating. Changes effected by ice storage were only slight. Frozen storage, in contrast, caused a significant decrease of adhesiveness measured after heating the fillets of both species.

Anwendungsmöglichkeiten instrumenteller Texturanalyse zur Charakterisierung industriell hergestellter Farcen

Commercially processed and for industrial purpose destined minces of several fish species were characterised with regard to their texture using texture profile analysis (TPA) of boiled specimen and by measuring the penetration force on raw minces as well as with regard to their colour by instrumental measurements of CIELab values. Concerning the parameters investigated the minces were in most cases significantly different. It was evident that the fish species is responsible for the functional properties of these intermediate products. For the TPA the influence of the measurement conditions was demonstrated and an appropriate method derived. IEF of proteins was used to verify the declared fish species. Unfortunately, this was not possible in all cases due to the lack of comparable pattern. Both the DMA and FA content were found to be in the normal range except those for saithe.

Factors affecting the susceptibility of salmonid fish to disease

A review article discussing the degree of susceptibility of fish to outbreaks of disease and whether, besides from changes in the physical and chemical characteristics of the environment, this susceptibility is instrumental in determining whether or not pathogenic challenge results in disease. The article summarises a decade of work on this subject at the Windermere laboratory of the Freshwater Biological Association and suggests possible directions for future research. The article covers experimental design, effects of environmental stress (including discussion on the hypothalamic-pituitary-interrenal (HPI) axis in salmonid fish), sexual maturation, research areas for future development and evolutionary considerations. There are a number of accompanying figures and images.