A correlation between seasonally changing photoperiod, whole body lipid, and condition factor in juvenile spring Chinook salmon (Oncorhynchus tshawytscha).

The regulation of lipid stores is a central process for the physiology and ecology of fishes. Seasonal variation in lipid stores has been directly linked to survival of fishes across periods of food deprivation. We assessed whether a seasonally changing photoperiod was correlated to seasonal changes in energetic status to help better understand these important processes.

Evaluation of endocrine and transcriptomic markers of male maturation in winter-run Steelhead Trout (Oncorhynchus mykiss).

Steelhead Trout (Oncorhynchus mykiss) display a varied life-history, including precocious male maturation at age-1 or age-2. In wild fish, precocious male maturation represents an important component of a diverse life-history portfolio. In hatchery programs, however, it is undesirable if rearing practices increase rates of early male maturation and reduce numbers of anadromous male adults.

Maintaining a wild phenotype in a conservation hatchery program for Chinook salmon: The effect of managed breeding on early male maturation.

In many salmonid species, age and size at maturation is plastic and influenced by the interaction between genetic and environmental factors. Hatchery reared salmon often mature at an earlier age and smaller size than wild fish. Modern salmon conservation efforts have focused on managing the level of gene flow between hatchery and natural origin fish to minimize potential genotypic and phenotypic change.

The pituitary-thyroid axis during the parr-smolt transformation of Coho salmon, Oncorhynchus kisutch: quantification of TSH β mRNA, TSH, and thyroid hormones.

The objective of this investigation was to quantify pituitary thyroid stimulating hormone (TSH) β mRNA, pituitary and plasma TSH and plasma thyroid hormone levels during the parr-smolt transformation of Coho salmon that occurs in spring from February to May. The status of the pituitary-thyroid axis was assessed using an RNase protection assay for pituitary TSH β mRNA and radioimmunoassays for salmon pituitary and plasma TSH and thyroid hormones. TSH β mRNA was highest during late winter (February) (4.

Androgen effects on plasma GH, IGF-I, and 41-kDa IGFBP in coho salmon (Oncorhynchus kisutch).

Among many species of salmonids, fast growing fish mature earlier than slow growing fish, and maturing males grow faster than non-maturing ones. To study the potential endocrine basis for this reciprocal relationship we examined the in vivo effects of the androgens, testosterone (T) and 11-ketotestosterone (11-KT), on plasma growth hormone (GH), insulin-like growth factor-I (IGF-I) and 41-kDa IGF binding protein (41-kDa IGFBP) (putative IGFBP-3) in coho salmon, Oncorhynchus kisutch. Immature male and female, two-year old fish (avg.

Central administration of corticotropin-releasing hormone stimulates locomotor activity in juvenile chinook salmon (Oncorhynchus tshawytscha).

This study evaluated the effect of corticotropin-releasing hormone (CRH) on locomotor activity, habitat choice, and social behavior in juvenile spring chinook salmon (Oncorhynchus tshawytscha). An intracerebroventricular (ICV) injection of CRH caused a dose-dependent increase in locomotor activity. The stimulatory effect of exogenous CRH on locomotor activity lasted for at least 24 h.