Swordfish

Exposure. The exposure of humans and animals to mercury from the general environment occurs mainly by inhalation and ingestion of terrestrial and aquatic food chain items. Pish generally rank the highest (10—300 ng/g) in food chain concentrations of mercury. Swordfish and pike may frequently exceed 1 p.g/g (27). Most of the mercury in fish is methyl mercury [593-74-8]. Worldwide, the estimated average intake of total dietary mercury is 5—10 p-g/d in Europe, Russia, and Canada, 20 pg/d in the United States, and 40—80 pg/d in Japan (27). 

Figure 12.1.1 The use of chemiluminescent lures in the commercial long line fishing industry to attract such deep sea fish as tuna and swordfish. Photo from Omniglow Corporation.

On a business trip, Felicia went out to lunch. The shrimp cocktail cost 5.95, the blackened swordfish with grilled vegetables cost 11.70, the cherry cheesecake cost 4.79, and the coffee was 1.52. What was Felicia s total bill not including tax and tip ... 

Monteiro, L.R. and H.D. Lopes. 1990. Mercury content of swordfish, Xiphias gladius, in relation to length, weight, age, and sex. Mar. Pollut. Bull. 21 293-296. 

Freeman, H.C., G. Shum, and J.F. Lithe. 1978. The selenium content in swordfish (Xiphias gladius) in relation to total mercury content. Jour. Environ. Sci. Health A13(3) 235-240. 

O2 concentrations, such as found in marine wetlands. High biomethylation rates have also been observed in coastal sediments. Because methylmercury is transferred up the food chain, the marine fish that occupy high trophic levels have very high mercury concentrations. In some cases, such as for tuna and swordfish, concentrations are high enough to pose human health risks. 

Although the rate of mercury input to the ocean s surface waters has increased as a result of anthropogenic activities, it is not clear that the relatively high MMHg concentrations now seen in the larger fish, e.g., tuna, shark, and swordfish, are the result of pollution. Measurements of mercury levels in preserved fish collected over the past 100 years have proven inconclusive due to small sample sizes and contamination effects. 

Escolar and oilfish are of low commercial values because of their kerrior-rheic properties. They are considered as "not suitable for catering" or even banned from sale in various countries. However, they are commonly marketed as a result of their substantial by-catch with tuna and swordfish (Shadbolt et. ah, 2002 Tserpes et ah, 2006). According to the European Communities (Labelling of Fishery and Aquaculture Products) Regulations 2003 (S.I. No. 320 of 2003), L. flavobrunneum and R. pretiosus must be marketed as escolar and oilfish, respectively, and no other commercial names can be used alternatively. Yet, both species are usually mislabeled as sea bass, butterfish, rudderfish, white tuna, or codfish either... 

Tserpes, G., Tatamanidis, G., and Peristeraki, P. (2006). Oilfish and shark by-catches of the Greek swordfish fishery in the E. Mediterranean A preliminary analysis applied to "presence-absence" data. Collect. Vol. Sci. Papers ICAAT 59, 987-991. 

The primary concern with organic mercury is methyl mercury in fish. Children and women of childbearing age should be cautious about consuming fish known to accumulate mercury such as tuna, shark, swordfish, and pike. Local fish consumption advisories should be followed. 

It should also be remembered that fish high in the food chain, such as tuna, swordfish, and shark accumulate toxic substances like mercury or PCBs. Mercury affects the nervous system and is a proven reproductive hazard. Table 13.4 lists examples of marine animals that may be toxic. 

From unpolluted areas From moderately Hg-polluted areas From highly polluted areas Swordfish, Xiphius gladius Muscle NW Atlantic Peru Pacific W. Atlantic Gibraltar Strait... 

Salmon, muscle Oysters, soft parts Shrimp, muscle Swordfish... 

The SOD of the swordfish Xiphias gladius remained fully active in 8 M urea. It was concluded from gel chromatography that active monomers were present But the value in 8 M urea of the SOD, presumably very stable in this medium, was obtained with standard proteins, considered unstable under these conditions. Bovine and yeast SOD showed also an apparent value of 16,000 in 8 M urea by gel chromatography after an abrupt decrease between 6 and 7 M urea. BESOD retained its full enzymatic activity, while yeast SOD was reversibly inactivated... 

The partial amino acid sequence of Gla-containing proteins from calf bone and swordfish bone shows that 21 of the 45 residues common to each are identical. The three Gla-residues and the single disulfide bond are in identical relative positions in the two proteins. An important difference between both proteins is the absence of 4-hydroxyproline in the swordfish protein638. The kidney has been localized as the site of vitamin K-dependent Gla-protein biosynthesis637. Gla has been reported to be a constituent of fossil bones639. ... 

Price, P. A., Otsuka, A. S., Poser, J. W. Comparison of 7-carboxyglutamic acid-containing proteins from bovine and swordfish bone Primary structure and Ca++ binding, In calcium binding protein and calcium function, p.333. Wassermann, R. A., Corradino, E., Carafoli,... 

This form of mercury tends to bioaccumulate so that organisms higher up in the marine food chain, such as pike, tuna, and swordfish, tend to have the highest levels. People who eat these fish regularly may be exposing themselves to high levels of mercury. 

Low Vitamin Bn content (0.5-5 micrograms/100 grams). Beef, cod, cheeses, chicken,eggs, flounder, haddock, halibnt, lamb, lobster, milk, pork, scallops, shrimp, swordfish, tuna, whale. 

High Vitamin D content (1.000 — 25 / 106 1. U./100 grams ).- Liver oils from Bonito, cod, halibut, herring, lingcod. sablefish, sea bass, soupfin shark, swordfish, tuna. 

Two types of protein have been isolated from bone and teeth. Osteocalcin457 is a gla protein synthesized in bone. Osteocalcin from various sources shows a high degree of sequence homology the protein from calf and swordfish has gla residues 17, 21 and 24. Human osteocalcin has gla residues 20 and 24, with residue 17 only partially carboxylated, a possible manifestation of... 

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