The sides shade to a lighter blue and then silvery-white on the belly. The colouration in the water, and even when on deck being measured and tagged, is a distinctive indigo blue and the origin of the sharks’ name. The teeth are ultra-sharp and any wounds from these when handling the fish can take a long period to heal due to the teeth being armed with an anticoagulant. The biggest giveaway is the serrated cutting edges to the pointed teeth. The nose is long and sharply pointed and it has 5-gill slits. It’s unmistakable long elongated body with a large upper lobe to the tail and the very long pectoral fins make identification easy. The blue shark is virtually impossible to mistake with any other shark. They are true ocean wanderers! How to identify a blue shark Tagged sharks have also travelled as far as South Africa. The superb results achieved by the tagging of blue sharks by the Irish Fisheries Boards has yielded some fascinating evidence of blue sharks travelling from Irish waters to the Azores and proving there is some interchange of sharks across the Atlantic Ocean east to west to North America. A small proportion of the larger sharks caught can be females that have pupped previously. Studies have shown that the majority of females that visit our waters are immature and the proportion of males to females is as low as sharks in the southern English Channel. The young are between 15ins and 18ins in length when born and instantly capable of fending for themselves. The females can give birth to 100 to 130 live young, but this number is very much dependent on the size of the actual mother, obviously, the bigger females having the biggest litters and smaller fish far fewer from four to maybe 60 as a guideline. There have been commercially proven fish bigger than this including a female apparently weighing 862lbs and around 15ft in length.įemale blues achieve maturity at five to six years of age, males at between four and five years. The male blue shark grows to a maximum size of around 9.5ft and maybe 300lbs or so in weight, but the females can grow to 12ft and with a more rounded body shape they can achieve weights closer to 500lbs. The modern practice of total catch and release means these fish were not claimed as records, but it proves the point that blue shark fishing is on an upward peak and the prospects for the future are positive. In recent years, the old blue shark record at 218lbs, which has stood since 1959, has been shaken by several fish over 200lbs and two definite fish that have easily exceeded that weight including one estimated by reliable eyes at the boat side at around 250lbs. Currently, in 2020, the average size is higher and around 60lbs with a higher number of bigger fish of 100lbs recorded. In the 1990s and first decade of the millennium, the average size of blue sharks was around 40lbs. This has been reflected in the average size of the blue sharks caught off the UK and Ireland. Although the effects of commercial long-lining and general over-fishing had a major effect on blue shark numbers through the 1990s and 2000’s inducing an inevitable serious overall decline, although not eradicated, the pressure of commercial fishing has eased somewhat of late and their numbers are now bouncing back. The blue shark is the more common of the big four sharks that are proven to visit the UK and Ireland annually alongside the porbeagle, thresher and mako. How to handle and photograph blue sharks.
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