Iodine Content of Wild and Farmed Seafood and Its Estimated Contribution to UK Dietary Iodine Intake

Iodine is an important nutrient for human health and development, with seafood widely acknowledged as a rich source. Demand from the increasing global population has resulted in the availability of a wider range of wild and farmed seafood. Increased aquaculture production, however, has resulted in changes to feed ingredients that affect the nutritional quality of the final product. The present study assessed the iodine contents of wild and farmed seafood available to UK consumers and evaluated its contribution to current dietary iodine intake. Ninety-five seafood types, encompassing marine and freshwater fish and shellfish, of wild and farmed origins, were purchased from UK retailers and analysed. Iodine contents ranged from 427.4 ± 316.1 to 3.0 ± 1.6 µg·100 g−1 flesh wet weight (mean ± SD) in haddock (Melanogrammus aeglefinus) and common carp (Cyprinus carpio), respectively, being in the order shellfish > marine fish > freshwater fish, with crustaceans, whitefish (Gadiformes) and bivalves contributing the greatest levels. Overall, wild fish tended to exhibit higher iodine concentrations than farmed fish, with the exception of non-fed aquaculture species (bivalves). However, no significant differences were observed between wild and farmed Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), and turbot (Psetta maxima). In contrast, farmed European seabass (Dicentrarchus labrax) and seabream (Sparus aurata) presented lower, and Atlantic halibut (Hippoglossus hippoglossus) higher, iodine levels than their wild counterparts, most likely due to the type and inclusion level of feed ingredients used. By following UK dietary guidelines for fish consumption, a portion of the highest oily (Atlantic mackerel, Scomber scombrus) and lean (haddock) fish species would provide two-thirds of the weekly recommended iodine intake (980 µg). In contrast, actual iodine intake from seafood consumption is estimated at only 9.4–18.0% of the UK reference nutrient intake (140 µg·day−1) across different age groups and genders, with females obtaining less than their male equivalents.

Ontogeny-Specific Skeletal Deformities in Atlantic Haddock Caused by Larval Oil Exposure

Bone deformities are one of the main effects of crude oil exposure in marine fish larvae. Craniofacial and jaw deformities, if severe enough, may restrict feeding and ultimately kill the developing larvae. This study aimed to examine the impact of dispersed crude oil on bone development in Atlantic haddock (Melanogrammus aeglefinus) larvae, a fish species spawning in areas approached for oil and gas exploration in the North Atlantic Ocean. Atlantic haddock larvae were exposed to low (60 μg oil/L), high (600 μg oil/L), or pulsed (0–600, average 60 μg oil/L over time) dispersed crude oil from 0 to 18 days post hatch (dph). Endpoints included survival and growth, bone integrity, and transcriptional parameters, which were assessed during (0–18 dph) and after exposure until the fish reached 8 months of age (243 dph). The results showed that the larvae in the high treatment group had reduction in growth at 2–19, 44, 134, and 243 dph. Craniofacial abnormalities were most severe at 8 and 19 dph. These deformities were not present at 44 dph, possibly because the larvae with deformed jaws failed to feed properly and died. Higher prevalence of spinal deformities was observed in haddocks that survived for 243 dph. Three genes encoding proteins critical for osteoblast function, sp7, postn, and col10a1, were downregulated in the high treatment group larvae. We discuss possible mechanisms of action in the developing larvae after oil exposure. In conclusion, this study shows that larval exposure to oil can potentially have long-term effects on growth and bone integrity in Atlantic haddock.

Cardiac dysfunction affects eye development and vision by reducing supply of lipids in fish

Developing organisms are especially vulnerable to environmental stressors. We aimed to understand the underlying mechanisms of phenanthrene (Phe) and crude oil induced eye malformations. We exposed Atlantic haddock (Melanogrammus aeglefinus) embryos to a known L-type calcium channel blocker, nicardipine hydrochloride (Nic), and compared to early embryonic crude oil (Oil) and late embryonic Phe toxicity. All treatments lead to severe, eye, jaw and spinal deformities at early larval stages. At 3 days post hatching, larvae from all treatments and corresponding controls were dissected. Eyes, trunk, head and yolk sac were subjected to lipid profiling, and eyes were also subjected to transcriptomic profiling. Changes in lipid profiles and the transcriptome suggested that the dysfunctional and abnormal eyes in our treatments were due to both disruption of signaling pathways and insufficient supply of essential fatty acids and other nutrients form the yolk.

Can vertical separation of species in trawls be utilized to reduce bycatch in shrimp fisheries?

Several shrimp trawl fisheries use a Nordmöre sorting grid to avoid bycatch of fish. However, small fish can pass through the grid. Therefore, the retention of juvenile fish often remains an issue during shrimp trawling. We investigated the vertical distribution of deepwater shrimp (Pandalus borealis) and dominant bycatch species at the point where the Nordmöre grid section is installed. This was achieved using a separator frame which split the net vertically into three compartments of equal entry size. Our results showed that shrimp predominately follow the lower part of the trawl belly, whereas species such as redfish (Sebastes spp.), cod (Gadus morhua), polar cod (Boreogadus saida) and American plaice (Hippoglossoides platessoides) preferred the mid-section in the aft of the trawl. Haddock (Melanogrammus aeglefinus) primarily entered through the upper section of the trawl belly. Using these results, we predict that a vertical separation device installed forward of a 19 mm Nordmöre grid combined with a 35 mm codend would result in a significant reduction in bycatch with only minor loss of shrimp.

A test of the provisioning hypothesis of recruitment control in Georges Bank haddock

The haddock (Melanogrammus aeglefinus) stock of the Georges Bank region of the US Northeast Continental Shelf displays a pattern of large, episodic recruitments. Among the hypothesized controlling mechanisms is the idea that recruitment events are related to provisioning of pre-spawning haddock by the fall bloom the year before. With the occurrence of a recent large recruitment event in 2013, it would be prudent to retest this hypothesis. Fall bloom magnitude was positively correlated (r=0.645, p=0.005) with haddock survivor ratio (recruits per spawning biomass) including data from the 2013 recruitment. This relationship identifies a pathway of bottom up control of a resource species, thus focusing concern over recent changes in lower trophic level productivity.