This research looked at the harm suffered by blue sharks. It found:
LARGE NUMBER OF BLUE SHARKS UNDER ATTACK FROM ANGLERS
"The blue shark is also the primary pelagic¹ shark species caught by recreational fishermen in the north-east USA from New Jersey to Maine. Although accurate estimates of total blue shark catch and release by the recreational sector are lacking, there is evidence from shark fishing tournament data that these numbers are high. In Massachusetts alone, a single 2-day shark fishing tournament in 1999 resulted in the catch of over 2000 blue sharks and 99% were released alive
(G. Skomal, unpublished data)."
THREE PERCENT OF SHARKS CARRY HOOKS INSIDE THEIR BODIES
"We found fishing hooks retained from previous fishing interactions in six (2.84%) of 211 adult male blue sharks landed by recreational fishermen in the western North Atlantic. Considering the numbers of blue sharks caught and released alive each year in the North Atlantic alone, one can estimate the potential number of sharks with retained fishing hooks to number in thousands."
NUMBER OF DEATHS UNKNOWN
"The high number of blue shark releases results in an unknown number of fish that do not survive as a result of physiological and physical trauma associated with hooking."
"The hooks were embedded within the distal oesophagus (n=3), or perforated the gastric wall (n=3) and lacerated the liver (n=2). The hooks were surrounded by excessive fibronecrotic tissue which ablated the normal anatomical structures and in the three sharks with oesophageal hooks caused partial luminal obstruction. Accompanying lesions included oesophagitis, gastritis, hepatitis and proliferative peritonitis."
"The mechanical injury caused by the fishing hooks was similarly complicated by bacterial colonization of the oesophageal tissues and the peritoneum, as well as by bacterial oesophagitis and gastritis."
"The mesothelioma-like peritoneal proliferations found in all examined sharks in this study possibly arose from the mechanical trauma and persistent irritation by a foreign body (corroding hooks), and from bacterial infection leading to severe, chronic peritonitis."
"Active inflammation associated with the hooks and intralesional bacteria were present in each of these sharks, and thus progression of the disease leading to debilitation or death cannot be ruled out."
¹pelagic - of the open sea