Sea Farms Research Articles

MICROBIOLOGICAL ASSESSMENT OF MUSSELS (MYTILUS GALLOPROVINCIALIS) FARMED AND COMMERCIALIZED IN CAMPANIA REGION

Mytilus galloprovincialis is one of the most commonly consumed bivalve molluscs. Several samples of Mytilus galloprovincialis were collected from different sea farms or bought in retail shops and from irregular peddlers. Total Mesophilic and Psicrophilic Aerobic Bacteria, Enterobatteriacee, E. coli, Salmonella spp., Vibrio spp. and L. monocytogenes were researched following ISO methods and EU Regulations. In mussels taken from the farms the limits were higher than those established by EU Regulation 2073/2005 only in one sample for E.coli and one for Salmonella spp. The mussels bought in retail shops showed good results and no sample exceed the law limits. Only one sample collected from irregular peddlers showed high levels of E.coli.

Effects of location and time of Pinctada margaritifera spat transfer from hatchery, on its growth and mortality in the sea

This study reports on the effects of different locations and hatchery transfer time on the growth and mortality of P. margaritifera spat. In the first experiment spat of P. margaritifera were transferred to the sea farms in Hendurabi and Lavan Islands at 25, 50, and 65 days post settlement and a Control was kept in the hatchery. Retaining spat in the hatchery more than 25 days after settlement did not improve the growth and mortality of juveniles. Spat grown in Hendurabi were significantly greater in size compared to those grown in hatchery and Lavan at the end of experiment (P < 0.05). Growth curve both in hatchery and sea farms best conformed to cubic model. In the second experiment, 55 days old spat from two propagation trials at a size circa 0.5 mm were deployed to the Hendurabi on 5th September and 7th October 2008 and were reared for five months accordingly. Spat of first deployment were significantly greater in size than second deployment at the end of experiment (P < 0.05). Maximum (0.34 mm d − 1 ) and minimum (0.11 mm d − 1 ) daily growth rate (DGR) were observed in September and October 2008 respectively. Mean DGR in fall was more than double in winter. There was positive correlation between water temperature and DGR, whereas food abundance, as expressed by concentration of chlorophyll-a, had a negligible effect.

허베이 스피리트호 기름유출사고를 통해 본 재난보도의 문제점

On 7 December 2007, the Hong Kong registered tanker Hebei Spirit, laden with 209,000 tonnes of crude oil, was struck by the crane barge Samsung No 1, whilst at anchor about five miles off Taean on the West Coast in Korea. About 10,500 tonnes of crude oil escaped into the sea from the Hebei Spirit. The recent oil leakage from a tanker in seas off Taean has turned the sea farms and fishing areas on the country`s western coast into a sea of oil. Analysts say the spill is considered as one of the world`s devastating sea pollution cases involving oil. In our contemporary society where people are exposed to potential dangers in every aspect, no one can be free from such dangers. With an increase in human casualties due to disaster, disaster reporting plays a vital role in preventing and minimizing damages. Despite such enormous significance, however, Korean disaster reporting has not performed effectively. In this contexts, this study analyzed the problems of disaster reporting in Korea, with the case of Hebei Spirit oil Spill in Taean-gun. And, this study suggest the establish ways and means needed to improve the disaster reporting in Korea with the case of Hebei Spirit case.

Comparison of IEF patterns of sarcoplasmic proteins of fish from North Atlantic and Aegean Sea

Identification of processed fish lacking morphological characteristics is of growing importance in the times of increasing global trade and illegal fishery. Protein electrophoresis techniques, like isoelectric focusing (IEF) of water-soluble proteins, are fast and inexpensive tools for identification of raw fishery products. Protein profiles of raw fish or fillet of the same species were found to be remarkably constant. However, it cannot be excluded that protein patterns of fish of the same species from distant stocks may show some variation. The protein profiles of commercially important fish from different fishing grounds were determined by collecting samples of 38 fish species from Aegean Sea and Turkish fish farms and of five species from North Atlantic waters. The raw fillet of the fish was analysed by IEF of water-soluble (sarcoplasmic) proteins. Species-specific protein profiles were obtained suited for identification of raw fish or fillet. When protein patterns and pI values were compared between Mediterranean and North Atlantic fish of the respective species, only minor differences were observed. These differences were related to the intensity of protein bands, but not to the position within the pH gradient of the IEF gel. The pI values (isoelectric points) of the prominent protein bands of the fish were determined to be used as a database.

Attached microalgae contribute to planktonic food webs in bays with fish and pearl oyster farms

2 Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577, Japan ABSTRACT: Planktonic food webs are primarily dependent on organic matter derived from phyto- plankton. In coastal areas, aquaculture has accelerated in recent decades, and attached algae and invertebrates proliferate on the farming cages. We hypothesized that the organic material on the farm structures is important to planktonic food webs and that the effects of aquaculture differ between fish (fertilized) and pearl oyster farms (not fertilized). To test these hypotheses, we examined the plank- tonic food webs at fish and pearl oyster farms using stable isotopes in the Uwa Sea, Japan. We col- lected zooplankton, particulate organic matter (POM, predominantly phytoplankton), attached algae, and macroinvertebrates in July 2005 and February 2006. Based on the isotope mixing model results, the attached microalgae contributed up to approximately 70% of the copepod food sources, and the contribution of attached microalgae to cyclopoid copepods was similar to their contribution to attached macroinvertebrates. Amphipods mainly fed on planktonic detritus from microalgae that had detached from the farm structures. The contribution of attached microalgae to copepod biomass was lower on the pearl oyster farm than on the fish farm. Our results show that attached microalgae from sea farms are important food sources for planktonic food webs in areas with fish farms and that the 2 food webs, attached and pelagic, are coupled through zooplankton grazing.

Alternative male life‐history tactics as potential vehicles for speeding introgression of farm salmon traits into wild populations

AbstractReleases of cultured organisms, such as farm Atlantic salmon (Salmo salar L.), threaten native biodiversity and the integrity of natural communities. Salmon escaping from sea farms, however, have relatively poor reproductive success, suggesting that the rate of spread of domesticated traits may be reduced. We now compare the relative reproductive success of males that mature precociously in freshwater (parr) and find that those of farm origin have higher breeding and fertilization success than wild and hybrid individuals. Specifically, hybrid parr had 57% and wild parr 25% the success of farm parr. Early maturing males could thus be important vehicles promoting introgression of domesticated and/or non‐native traits into wild populations and ultimately have long‐term impact on the genetic integrity of native populations.

Chemical and biological remediation of the benthos near Atlantic salmon farms

Salmon farms in British Columbia now typically produce over 2000 mt of fish during each 18- to 24-month production cycle. An 18-month study of Stolt Sea Farms' Arrow Pass farm was undertaken in 1996 to examine the spatial and temporal extents of chemical and biological benthic effects. Microbial metabolism of farm biodeposits in nearfield sediments resulted in increased sulfide concentrations and decreased redox potential. These physicochemical changes modified the macrobenthic community. Species sensitive to enrichment were quickly extinguished from the immediate vicinity of the farm and were replaced by the organic carbon tolerant opportunistic annelids Capitella capitata and Ophryotrocha cf. vivipara. These effects extended to at least 50 m from the net-pen's perimeter on the downcurrent transect. Chemical remediation, defined as a return to reference levels of organic carbon, a reduction in free sediment sulfides to <960 μM and an increase in sediment redox potential to reference conditions, began as soon as the harvest commenced and was complete by the end of harvest. Biological remediation began during the harvest and was complete within 6 months of fallow. Annelids and crustaceans recruited first into the remediating sediments and were followed by at least two seres of mollusks. Routine quarterly monitoring of sediment-free sulfides, redox potential and total volatile solids (TVS) at four Stolt Sea Farms' tenures from 1999 through present has demonstrated that sediment sulfides increase rapidly during the early stages of production and decrease equally quickly during harvest. Fallow periods of 4–6 months appeared adequate for complete chemical remediation at the tenures examined. Elevated concentrations of zinc, which is added as a supplement to salmon feeds, have been observed in sediments. However, they are bound by sulfides and are not biologically available. Zinc concentrations declined to background during chemical remediation. No cumulative effects associated with either organic carbon or zinc were observed at any of these farms during successive production cycles.

When aquaculture restores and replaces an overfished stock: is the conservation of the species assured? The case of the scallop Argopecten purpuratus in Northern Chile.

The fishery for Argopecten purpuratus in northern Chile, whichcollapsed because of overfishing, has been replaced by aquaculture of thespecies. In 1998, cultures produced 16,474 t, while the highest landings recorded inthe entire history of the fishery was in 1984 (one year after the 1983 ElNino) with 5275 t. The figures for stock size of the species in the pastand at present, show that the wild stock of scallops today represents notmore than 10–15% of the total stock of the species within Chile, with mostof the individuals being kept in sea farms. Thus it is concluded that thescallop already represents a domestic species and, considering theoccurrence and development of selection practices in sea farms,biodiversity within the species appears to be at risk. With the developmentof culture practices over its entire range, there is little use in trying torecover a wild fishery for this scallop. It is urgent, however, that selectednatural beds be protected in order to preserve genetic diversity.

Stability of astaxanthin and canthaxanthin in raw and smoked atlantic salmon ( Salmo salar) during frozen storage

The objective of the present study was to establish the effect of frozen storage and smoking on the stability of astaxanthin and canthaxanthin in farm raised salmon. Salmon samples were obtained from two sea farms where they had been maintained on commercial feeds containing either astaxanthin or canthaxanthin. The results showed that there was no significant change in visual colour score or carotenoid content of astaxanthin-fed fish during frozen storage for up to 12 weeks. However, smoking fish from this group after frozen storage for 6 and 12 weeks significantly decreased pigment content from an initial level of 9.39 ± 0.23 to 7.99 ± 0.08 and 7.26 ± 0.07 mg kg −1, respectively. Furthermore, Hunter L and a ∗ values of raw fish were affected at 6 weeks but not at 12 weeks of storage. Significant changes were measured in canthaxanthin-fed fish stored for up to 12 weeks at −20 °C. Visual colour scores decreased and carotenoid content of the flesh decreased from 10.6 ± 0.27 to 4.36 ± 0.2 mg kg −1. Hunter L values increased, while a ∗ values decreased. Smoking canthaxanthin-pigmented fish had no significant effect on the carotenoid content.

Plasma ammonia and urea levels in Atlantic salmon farmed in sea water

Plasma ammonia and urea levels were measured in feeding Atlantic salmon Salmo salar L. reared in two different commercial Norwegian sea farms. A very large individual variation of the plasma ammonia and urea levels in addition to the large influence of several factors suggest that it may be difficult to use these parameters in diagnostic work on fish.

Practical aspects of bacterial culture for the diagnosis of bacterial kidney disease (BKD)

A study was made of practical aspects of culture of Renibacterium salrnonjnarum (R.s.) from the kidney of Atlantic salmon Salmo salar. Samples were taken from fish in sea farms affected by outbreaks of bacterial kidney disease (BKD). Only 67% of the samples positive for growth of R.s. on kidney disease medium (KDM2) were positive on selective kidney disease medium (SKDM). Of the samples positive on KDM2, 98 % were identified as positive after 8 wk of incubation a t 15 C, whereas only 82 is of the samples positive on SKDlvl were positive at this time Growth of R.s on KDM2 produced more colonies than growth on SKDM No significant differences in isolation frequency were seen betureen culture from anterior and poster~or k ~ d n e y . If 3 or 4 ~nocu la t~ons were made from each fish, the number of R.s.-poslt~ve f ~ s h increased by 44 0/,) in the lightly infected population of thls study. Both storage of the sample material on swabs in 2 different niodifications of Stuart's transport medium for 24 h, and freezing a t -20 C for 3 to 4 mo, reduced the sensitivity of culture from lightly infected samples.

Detection of infectious pancreatic necrosis virus (IPNV) RNA by hybridization with an oligonucleotide DNA probe

Marine farming of Atlantic salmon ( Salmo salar) is growing rapidly in Norway, and fish diseases have now become one of the biggest obstacles for this new industry. Infectious pancreatic necrosis virus (IPNV) is commonly found in fish from Norwegian sea farms. Diagnosis of IPNV infection is, at present, mainly based on virus isolation in cell cultures and identification by neutralization tests (NT). A DNA-RNA hybridization assay was developed using a 24 base DNA oligonucleotide probe. This is homologous to a part of the nucleotide sequence of the IPNV genome coding for a protease. RNA extracted from IPNV and harvest from infected cell cultures were fixed to nylon filters and hybridized with the 32P end-labelled probe. The results showed that the probe specifically identified IPNV from these two materials, both for the three different virus strains (Ab, Sp and VR-299) used, and for several different field isolates. It did not hybridize with reoviruses or non-infected cell cultures used as controls. These results indicate that the probe is not serotype specific, and furthermore that RNA extraction is not required before hybridization. This method may be a useful alternative to NT for routine identification of IPNV, particularly when non-radioactive labelling of the probe is introduced.