Did you know that there is a dump shark? I don’t know why the Centrophorus harrissoni was named like that, but I find it insulting.

Harrisson’s Dogfish, Centrophorus harrissoni. Source: CSIRO National Fish Collection. License: CC BY Attribution

The Harrisson’s Dogfish is a rare species of gulper sharks with a large mouth and large green eyes. It can live up to 43 in -110 cm- long and up to 46 years old. Maturing late (females at about 39 in -99 cm- and males at about 33 in -84 cm- length), female gives birth to mostly only one living young (ovoviviparous) with about 13 in -35 cm- length every two (or possibly three) years (it seems that only their right-side uterus is working properly).

Living solely along the east coast of Australia and off New Zealand and at a relatively high area for a deepwater shark (at 820 to 1260 ft -250 to 385 m- under water), the Harrison’s Dogfish was considered Critically Endangered in 2003. This was based on a more than 99% decline of the species on upper continental slope grounds off central and southern New South Wales (NSW) and eastern Victoria, compared with the 1970s (when commercial trawling began on the NSW upper slope). The species is now known to occupy a greater geographical range than previously thought and a number of conservation measures have been implemented. Earlier restrictive catch limits (to prevent target fishing for its meat und squalene in its liver oil) have been replaced by a total ban on retaining any Harrisson’s Dogfish for sale. There are protection areas (where all kind of fishing are banned), others where only some fishing methods are banned, and a ban on trawling below 2296 ft -700 m- along the east coast south from Sydney (designed to protect all deepwater sharks). The low reproductive rate, late age of maturity, and long lifespan typical of these sharks means they are likely unable to recover quickly after their depletion, despite the fishing ban. Upper-slope dogfish species are more vulnerable to capture than mid-slope species, because they are targeted throughout their vertical distribution and most of their local geographic distribution (except for the protection areas). But since they are used to light and lower water pressure, a high proportion of those captured accidentally are likely to survive if returned quickly to the sea.

The Harrison’s Dogfish is considered as only Endangered, since now the overall population decline is thought to be only 70% (although it will be most likely declining further). Scientists hope that 500 of them will be enough for a genetically diverse population. To me, these numbers mean that this species is almost extinct (In comparison, there are more than tree times as many giant pandas in the wild, and their numbers are increasing further. But they are cute.).

Sources: here, here and here

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