摘要:

The detection of starvation is a major problem in fish husbandry. Too often the discovery of starving animals is not made until pathogenic organisms are about to overcome the weakened animals. A simple test, using a commercial plastic strip with a reagent area that changes colour in the presence of starvation‐induced ketones, was applied to this problem in the mullet,Mugil cephalus.The strip identified ketones in the fish skin mucus, and demonstrated its value in detecting starvation in fishe

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04156.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Among hatchery bredSparus aurata, 5.4% of the offspring of a single parent pair showed severe skeletal deformations coupled with marked growth retardation and pathological changes in the swimbladder. This resulted from extreme proliferation, then hypertrophy, of the cuboidal epithelial cells of the gas gland and proliferation of the rete mirabile. This caused almost complete congestion of the swimbladder air space. The nature of the pathological changes in the swimbladder and the possibility of hereditary origin for both the skeletal and swimbladder deformations are discussed.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04157.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Hinds and groupers (Teleostei, Serranidae) form a valuable component of catches of reef fishes in the Caribbean Sea and adjacent regions. Investigations of species in Jamaican waters have covered relative and absolute growth rates, spawning seasons, fecundity, size at maturity and at sex change, and size compositions, mortality rates, and relative abundances of exploited and unexploited populations.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04158.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Samplesof Eubothrium salveliniandE. crassumwere obtained from resident and migratorySalvelinus alpinusandSalmo truttaand fromS. salarat sea from North Norway and the islands of Spitsbergen and Jan Mayen. Scolex dimensions proved an unsuitable character for identifying these two parasite species, and use of alternative characters confirmed thatE. salveliniis specific toSalvelinusandE. crassumtoSalmo.Distributions of both species are co‐extensive with their hosts, but levels of infection in any locality relate to the abundance of zooplankton.E. salveliniexhibits seasonal maturation and incidence cycles in char. It is recognised as being a freshwater parasite, although some individuals can survive the period of marine migration of sea char. Returning migrant char may contain such individuals together with small plerocerciform parasites acquired almost immediately upon their re‐entry to freshwater. No evidence for marine infections withE. salveliniwas found. The presence of plerocerciform and gravid adultE. crassumin salmon caught at sea confirms the existence of a marine life cycle and a marine race in this species. In salmon moving from one medium to the other the marine and freshwater races replace each other, but in sea trout, which spend shorter periods at sea, complete replacement may not occur and at any one time fish may harbour individuals of both races. Recognition of the existence of two races clarifies much of the confusion surrounding the biology of this spec

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04159.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Scanning electron microscope studies of fish epidermis demonstrate whorled arrangements of microfolds on the surface of superficial epidermal cells in the following species of teleost fish: the guppyfishPoecilia reticulata(Peters), the goldfishCarassius auratus auratus(L.), and the clown anemone fishAmphiprion percula(Lacépède). The pattern is most pronounced in epidermal cells covering the scales, but is also seen in the epidermal cells of the tail and body fins. The whorled pattern was not present on the gill epithelium or the surface of the eyes. These observations differ from transmission electron microscope studies which have described the skin surface as being composed of microvill

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04160.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

The occurrence of hybrids between chub,Leuciscus cephalus, and roach,Rutilus rutilus, from three rivers in England is reported. The hybrids are described and illustrated, and means of identification are indicated. Chub X roach hybrids, like those between other leuciscine cyprinid species, can be positively identified by the number and form of the pharyngeal teeth.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04161.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

The karyotypes of the two species of the gobiid fish genusQuietula, Q. y‐cauda(Jenkins&Evermann) andQ. guaymasiae(Jenkins&Evermann), are reported for the first time. The karyotypes contained equal numbers of chromosomes (2n=42) but differed in chromosome morphology.Quietula y‐caudahas 42 acrocentric chromosomes.Quietula guaymasiaehas six metacentric, four submetacentric, and 32 acrocentric chromosomes. It is suggested the karyotype ofQ. guaymasiaemight have been derived from that ofQ. y‐cauda.In addition, from comparison of the species' karyotypes of the generaQuietulaandGillichthys, it is possible the karyotype ofQ. y‐caudamight have been derived from that ofGillichthys mi

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04162.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

JuvenileSarotherodon mossambicuswere exposed to a daily dose of 1 or 2 p.p.m. of the antigonadotropic drug methallibure for a period of seven weeks. The control fish all showed well‐developed gonads and a considerable concentration of astaxanthin in the dorsal fins. The dominant male showed a much higher astaxanthin value than the other fishes. Methallibure completely prevented gonad development. Nevertheless, some astaxanthin deposition did occur in the drug‐treated f

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1978.tb04163.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY