Impacts on whales, sharks and fish - The Great Barrier Reef: An Environmental History - page 113

Impacts on whales, sharks
and fish
Introduction
The previous two chapters have described historical human impacts on marine
turtles and dugongs, which are comparatively well-researched, charismatic mega-
fauna of the Great Barrier Reef and its adjacent waters. In contrast, impacts on
some other marine wildlife species in the region are less known. This chapter
focuses on historical impacts on some types of whale, shark and fish, although some
of those impacts can be reconstructed only partially, due to the paucity of records.
While several species of cetaceans are found in the GBRWHA, comparatively
little is known about those animals and, even in the year 2000, the population
sizes of all species except for humpback whales ( Megaptera novaeanglia ) were
unknown (GBRMPA, 2000). This chapter describes the humpback whale fishery
in the Great Barrier Reef, for which some documentary evidence illuminates
the period 1952-1962. The humpback whales found in the Great Barrier Reef
migrate between feeding grounds in Antarctic waters and breeding areas in
coastal Queensland; along parts of the Queensland coast, their migration routes
bring the animals close to the shore. In those places, the animals are particularly
vulnerable to anthropogenic impacts from the adjacent coast. Furthermore,
the species is characterised by a long-lived, slow-reproducing life history, with
high investment by lactating cows in their calves. Those characteristics impose
additional vulnerability on the species in Queensland waters where cows and
calves are susceptible to human impacts. GBRMPA (2000) identified numerous
anthropogenic impacts on cetaceans, including commercial whaling, harassment,
vessel strikes, entanglement in nets, ingestion of litter, underwater explosions,
pollution (including noise pollution), disease, live capture and habitat
degradation. In addition to historical impacts on humpback whales, this chapter
also briefly considers some of the major impacts on sharks and fish in the Great
Barrier Reef, although both of those subjects require more detailed, dedicated
investigation.