摘要:

Toxicity of Wescodyne(R)and Betadine(R)to eyed eggs was not adversely affected by water hardness (as calcium and magnesium) or by exposure periods up to 60 min. Both iodophors were much more toxic below pH 6.0 than at pH 8.0. In general Wescodyne was slightly more toxic than Betadine. Significant egg loss occurred if freshly fertilized eggs were water-hardened in either iodophor at 100 ppm of iodine, but egg loss at 25 ppm of iodine or at 100 ppm if the eggs were disinfected 30 min after water hardening was comparable to the control. Also, there was no effect on the egg mortality or fry development following single or multiple exposures after eggs were water hardened. At pH 6.0 and above, Wescodyne and Betadine at 100 ppm iodine in a 15-min dip would be safe to use on rainbow trout eggs at any stage of development after water hardening. Recommendations and precautions for hatchery use are given.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<73:CTOTIT>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Repopulation after a fish kill caused by pesticide pollution in Mud Creek, Washington County, Arkansas is reported. Twenty-nine species of fishes were eliminated from the study area as a result of the poison. Repopulation began almost immediately after the pesticide dissipated, and was accomplished primarily by immature individuals. Chronology and rate of repopulation of each species are reported, and factors influencing the rate of repopulation and population structure are discussed.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<79:RAAFKI>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Monthly changes in mean ova diameter and gonadal weights indicated that spawning of rough shiner, Notropis baileyi, a cyprinid recently introduced in Halawakee Creek (Apalachicola River Drainage), Alabama, occurred during early or middle May through late September or early October. Peak spawning occurred in early or middle June. Several complements of ova matured. Fecundity was linearly related to length and weight of the fish. No significant correlation existed between the diameter of ova and fork length of fish. Versatile food habits, a long successful spawning season and favorable habitat are believed to be the key to the success of this shiner in Halawakee Creek.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<88:RBOTRS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Dolphin caught by charter boats fishing over the Continental Shelf in 1961–63 were examined to determine food habits and sex ratios. Most important prey (listed according to percent of total prey weight) were: Exocoetidae (26%), Scombridae (22%), Carangidae(12%), Balistidae (9%), and Coryphaenidae (5%). Males constituted a significant majority (61%) of large dophin (801–1,275 mm fork length). Most (71%) small dolphin (450–600 mm) were females. Large dolphin of both sexes were generally captured in open water, while small female dolphin were usually associated with tide-lines (areas where current patterns cause accumulations of floating Sargassum and other flotsam). In 1963, tide-lines were infrequently encountered by charter boats. Decreased charter boat catches, increased abundance of young males in the fishery, and impaired foraging by small female dolphin resulted. We hypothesize that male dolphin (which are heavier than females of similar length) leave the sanctuary of the tide-line at an earlier age than females to forage for large prey in the open ocean. Thus, most small dolphin captured near tide-lines and associated flotsam are females. Most large dolphin captured by trolling are males, because their significantly greater weight per unit of length results in more voracious feeding and increased selection by the charter boat fishery.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<94:FHASRO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Parasites were studied from the gill and buccal areas of 145 dolphin, Coryphaena hippurus Linnaeus, caught in the Straits of Florida. Dolphin were infested with a digenetic trematode, Bathycotyl branchialis Darr, and copepods, Charopinopsis quaternius Wilson, Caligus belones Krøyer, C. bonito Wilson, C. coryphaenae Steenstrup and Lutken, C. patulus Wilson, C. productus Dana, C. quadratus Shiino, and Euryphorus nordmanni Milne-Edwards. Parasite-mix, incidence, and intensity of infestation increased with increase in host size except that Caligus bonito and Charopinopsis quaternius were not found on fish larger than 1,000 mm. No significant relationships were found between host sex and parasite-mix, incidence, and intensity of infestation. Seven pairs of parasite species showed either positively or negatively significant interrelationships. C. hippurus is a new host record for Caligus bonito, C. patulus and Bathycotyl branchialis.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<101:POTGAB>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Marked sub-adult white shrimp were released in Galveston Bay in August 1963. Recoveries indicated there was no emigration from the bay between August and mid-October. Using the Bertalanffy growth function estimates of L∞equals 214 mm, K = 0.09 (sexes combined). Shrimp increased rapidly in size, 98 to 133 mm in 4 wk and to 146 mm in 6 wk during the warm summer months. Reliable estimates of natural and fishing mortality could not be obtained. Several techniques were used to obtain estimates but they varied to such a degree that results were questionable. Probable causes of these inaccurate estimates are nonrandom distribution of the marked population, fishing effort, or a combination of both.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<107:AWSMS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

An inoculum was taken from the kidneys of 777 fish of 10 species from Clear Lake, Iowa, in 1970 and 1971. Aeromonas liquefaciens and Pseudomonas sp. were present in the different fish species at rates of 0 to 50%. A trend of higher carrier rate in the warm months was evident for several species.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<114:POPPBI>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

White perch age and growth data were obtained from 1,706 fish collected in a 63-km section of the lower Connecticut River between 1966 and 1969. Peak annulus formation occurred from late April to mid-May and fish formed their scales around 20 mm standard length. Most growth (53%) occurred in the first 2 yr of life. Growth rate was faster than in 15 other populations. Growth in the upper Connecticut River was similar to that of the species in the lower river for the first 2 yr of life, but thereafter none of the populations grew as fast as white perch in the lower Connecticut River. Longevity was lowest in the Connecticut River and other waters of Connecticut, maximum observed age being seven. Older fish have been found in all other white perch populations. The length-weight relationship was Log W(g) = -1.425 + 2.891 Log L (r = .96). There was a reduction in the average calculated length in all age classes in each succeeding year. This trend is directly opposite that of Lee's phenomenon and suggests possible stunting.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<117:AAGOTW>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The migration of Macrobrachium ohione during its spawning season was observed from 1969 to 1971 in the Galveston Bay area. Maximum activity was at night and during the new moon. Rainfall seemed to be associated with increased movement. Salinities near 15 ‰ appeared to act as a barrier to movement of this species into the Galveston Bay system.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<120:NOTRSM>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The most frequent food items in 185 coho salmon (Oncorhynchus kisutch) stomachs were insects, but fish comprised the most food by volume. The coho ranged from 190 to 444 mm total length and were collected during all seasons of the year. As the coho grew, fish comprised a greater part of their diet. No well defined pattern of insect feeding in relation to coho size was apparent. The percent frequency of fish ingested was highest during the winter (69%) and was 40% or less during other seasons. The percent volume of fish in the diet was over 58% in each season, and the highest percent volume of fish was consumed during the winter (93%).

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<126:FHOCSO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor