Tunas and their relatives dominate the world's largest ecosystems and sustain some of the most valuable fisheries. The impacts of fishing on these species have been debated intensively over the past decade, giving rise to divergent views on the scale and extent of the impacts of fisheries on pelagic ecosystems. We use all available age-structured stock assessments to evaluate the adult biomass ...

We used an isometric muscle preparation to test the hypothesis that yellowfin tuna Thunnus albacares utilize the intracellular Ca2+ storage sites of the sarcoplasmic reticulum (SR) during routine contractions. Ryanodine (a blocker of SR Ca2+ release) reduced the force of contraction by approximately 50 % and the rates of contraction and relaxation by 60 % in yellowfin tuna atrium. High levels o...

Introduction Do billfish and tuna distinguish colours? This question has captivated both fishermen and scientists for years. Proving colour vision in this group of fish is particularly difficult since behavioural colour discrimination experiments—the “final proof” of colour vision ability in any animal—are impossible to undertake with such large open ocean fish. Instead, scientists have aimed t...

We answer four questions about tuna management in the eastern Pacific Ocean: What are the management objectives? Are they reasonable? Can we determine whether they have been achieved? Have they been achieved? There are explicit, overarching management objectives including keeping populations at levels that will permit maximum sustainable yields, consideration of the precautionary approach, and ...

A noncovalently bound, ordered complex consisting of fragments (1-25)H and (14-103) derived from tuna cytochrome c has been prepared and characterized. The equilibrium properties of this complex are indistinguishable from those of the corresponding complex, (1-25)H X (23-104), of horse cytochrome c. The tuna species possesses a second tryptophan residue (at position 33 of the amino acid sequenc...

Autoxidation of oxyhaemoglobin (oxyHb) to methaemoglobin was measured at different temperatures in haemoglobin solutions from Atlantic hagfish, river lamprey, common carp, yellowfin tuna and pig. The aims were to evaluate the impact of the absent distal histidine in hagfish haemoglobin, the importance of oxyHb being either monomeric (hagfish and lamprey) or tetrameric (carp, tuna and pig) and t...

To evaluate the effects of acute protein loading on the glomerular filtration rate, albumin excretion rate and concentration of plasma amino acids, ten healthy volunteers and six type 2 diabetic patients with normoalbuminuria were studied before and after eating 0.7 g/kg body weight of tuna fish, boiled egg white, cheese or tofu (bean curd) on separate days. Furthermore, to study the possible r...

Electronic tags were used to examine the seasonal movements, aggregations and diving behaviors of Atlantic bluefin tuna (Thunnus thynnus) to better understand their migration ecology and oceanic habitat utilization. Implantable archival tags (n = 561) were deployed in bluefin tuna from 1996 to 2005 and 106 tags were recovered. Movement paths of the fish were reconstructed using light level and ...

Owing to the inherent difficulties of studying bluefin tuna, nothing is known of the cardiovascular function of free-swimming fish. Here, we surgically implanted newly designed data loggers into the visceral cavity of juvenile southern bluefin tuna (Thunnus maccoyii) to measure changes in the heart rate (fH) and visceral temperature (TV) during a two-week feeding regime in sea pens at Port Linc...