It’s February, finally the weather can get better (or worse) since the fog seems to be getting even thicker and thicker. Last week we were awakened by a cock crow as we celebrated the Year of the Rooster with the Red Jungle Fowl. This week an altogether annoying sound is making an appearance…sounding…uhm you know what I mean. Hope you guys enjoy.

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Issue #159 – Plainfin Midshipman

Kingdom – Animalia

Phylum – Chordata

Class – Actinopterygii

Order – Batrachoidiformes

Family – Batrachoididae

Genus – Porichthys

Species – notatus

Related Species - Plainfin Midshipmen are members of the Toadfish Family (1)

Range - Plainfin Midshipmen live in the intertidal coastal zone along the west coast of Canada, the USA and Mexico.

The ‘Hum’

Plainfin Midshipmen are olive brown fish that reach a length of almost 40cm, with large pale pectoral fins. Males are generally larger than the female fish, although the gender is dimorphic with large Type I males and small Type II males occurring naturally in the wild. Both male and female fish are able to breathe air, and can often be found sheltering in rocks on land at low tide as it waits for the water to return. In its more southern range the Plainfin Midshipman is bioluminescent (2), and has an array of green photoreceptors covering its body which resemble the buttons on a naval uniform, hence the ‘Midshipman’ part of this fishes common name.

This biolumincent ability comes from certain types of crustacean from the genus Vargula (which is also bioluminescent) that this fish feeds on. In addition Plainfin Midshipman also feed on small crabs and fish which it catches at night when it is most active. In areas where their ranges overlap, Plainfin Midshipmen are an important food source for the chicks of the Bald Eagle (Haliaeetus leucocephalus), mostly because they live in shallow water and are slow moving. To reduce the risk of predation, the fish usually spends the daylight hours hidden under rocks or buried under the sand.

When it comes time to breed, the strategies of the two types of Plainfin Midshipmen differ. The large Type I Males releases a long continuous hum, for up to an hour, to attract gravid females to his position. When the female reaches his position she lays her eggs and leaves, with the male fertilises them, usually after adding the eggs of more females he attracted to his nest. Sometimes however a Type II Male, who looks and sounds like a female, will be attracted to the nest and take a chance at fertilising the eggs himself. Whatever the case, with up to 1000 eggs in his nest, the resident Type I Male guards his precious brood and the larvae they hatch into until they reach their juvenile phase, something that occurs around forty days after the initial fertilisation (3).

Five Awesome Aquatic Noises

Despite seeming quiet, underwater environments are often as noisy as their terrestrial counterparts. Pacific Herring (Culpea pallasii) for example, communicate the locations and types of nearby predator with their shoal mates by farting. Even starved fish are able to warn their fellows, suggesting that it is more than just nerves or indigestion (4).

Some of the loudest underwater animal noises come, unsurprisingly from whales, with the hunting clicks of the Sperm Whale (Physeter macrocephalus) being the loudest of all animals calls reaching a volume of 220 decibels.

The Sperm Whale does have competition for the title of the loudest animal from the Pistol or Snapping Shrimps (Family: Alpheidae) which by clicking their oversized claws can create a click with a volume of 215 decibels, to stun prey. In addition to creating sound, the collapse of the super cavitation bubble created by the click produces a brief flash of light that has a thermal output of 4700°C.

Relative to its size, the loudest sound is created by the male Lesser Water Boatman (Micronecta scholtzi) a freshwater insect often found hanging under the surface of ponds and lakes. By rubbing his penis against grooves on his abdomen, the Boatman can create sounds with a volume of 100 decibels (5). At only a centimetre in length, the Boatman would create sound of over 300 decibels if scaled up to the size of an average Pistol Shrimp (which are about 3 to 5 cm in length),

Unlike whales, sharks are mostly mute with only a single species making sounds. The Draughtsboard Shark (Cephaloscyllium isabellum) which swells up as a defensive measure against predation. When it relaxes the muscles that made it puff up, the escaping air makes a call that sounds like a brief bark.

Bibliography

1 - www.arkive.org

2 - Thompson, E. M., et al. (1988). Induction of bioluminescence capability in the marine fish, Porichthys notatus, by Vargula (crustacean) (¹⁴C)luciferin and unlabelled analogues. J. Exp. Biol. 137 39-51.

3 - Craig, P. M., et al. (2013). Coping with aquatic hypoxia: How the plainfin midshipman (Porichthys notatus) tolerates the intertidal zone. Environ Biol Fish.

4 - http://news.nationalgeographic.com/news/2003/11/1110_031110_herringfarts.html

5 - https://www.wired.com/2011/07/insect-penis-sound/

Picture References

1 - http://ocr.org/ocr/wp-content/uploads/8086393322_cb8f1bf95e_k-597x406.jpg

2 - http://4.bp.blogspot.com/-jyzIQmycqOI/Tg5JlwK6PnI/AAAAAAAABLg/9DkOjqh46-E/s1600/Plainfin+Midshipman+and+eggsDSCF4220+%25284%2529.JPG

3 - http://i.imgur.com/aPvFgr9.gif

4 - http://www.wildaboutbritain.co.uk/pictures/data/18/medium/lwb-3.jpg

There’s no need to yell, well not if you’re inland away from all these noisy animals. Next week’s animal is a beastie I like to affectionately call ‘Ole Sawtooth’, which makes it sound like a horror villain. To find out if it is we’ll have to wait until next week, but until then make sure to critic, comment and suggest future issues as well as making sure you check past issues in Impurest’s Bestiary

Many Thanks

Impurest Cheese

Want more IGTA? For a totally awesome issue about like the Sarcastic Fringehead, click here. Or for something more serious, click here to meet the incredibly endangered Devil’s Hole Pupfish.