Tuna and Mackerel Relatives: Family Scombridae

There are approximately 55 species of fishes in the family Scombridae, which are collectively referred to as scombrids.  Scombrids range in size from small baitfish like mackerel to giant bluefin tuna which are some of the largest boney fish in the sea.  Yet, despite the size range of fishes in this family, one thing is universal - they're built for speed.  

Speed adapations

When you look at a tuna or mackerel, there are a few things you'll notice.  The first is how streamlined they are.  Scombrids are built like torpedoes. Every part of their body is streamlined. The fins on a scombrid lie flat against the body when it swims so that there is no drag.  The dorsal fins even fold down into small groves on the top of the fish.  The caudal fin is extremely stiff allowing the fish to get maximum thrust out of body movements.  In larger fish, especially those that live in cold waters, swimming muscles are kept warm by a unique ability to thermoregulate their body temperature. 

Thermoregulation

Just like penguins that are able to reduce the amount heat they loose as they stand on the ice, scombrids like tuna are able to keep their core body temperatures high as they swim in cold waters.  To do this they use a type of counter-current circulation whereby their arteries and veins are positioned side by side as they care blood too and from the outside of their bodies.  This allows the fish to maintain core body temperatures from 75 to 95 degrees Fahrenheit.  Just as warm fingers work better for we humans, the higher a fish's body temperature, the more efficient its muscles work.

Classification

The following species and subspecies are extant scombrid fishes:

• Acanthocybium solandri - Wahoo
• Allothunnus fallai - Slender tuna 
• Auxis rochei eudorax
• Auxis rochei rochei - Bullet tuna
• Auxis thazard brachydorax
• Auxis thazard thazard - Rigate tuna
• Cybiosarda elegans - Leaping bonito
• Euthynnus affinis - Kawakawa
• Euthynnus alletteratus - Little tunny
• Euthynnus lineatus - Black skipjack
• Grammatorcynus bicarinatus - Shark mackerel
• Grammatorcynus bilineatus - Double-lined mackerel
• Gymnosarda unicolor - Dogtooth tuna
• Katsuwonus pelamis - Skipjack tuna
• Orcynopsis unicolor - Plain bonito
• Rastrelliger brachysoma - Short mackerel
• Rastrelliger faughni - Island mackerel
• Rastrelliger kanagurta - Indian mackerel
• Sarda australis - Australian bonito
• Sarda chiliensis chiliensis - Eastern Pacific bonito
• Sarda chiliensis lineolata - Pacific bonito
• Sarda orientalis - Striped bonito
• Sarda sarda - Atlantic bonito
• Scomber australasicus - Blue mackerel
• Scomber colias - Atlantic chub mackerel
• Scomber scombrus - Atlantic mackerel
• Scomberomorus brasiliensis - Serra Spanish mackerel
• Scomberomorus cavalla - King mackerel
• Scomberomorus commerson - Narrow-barred Spanish mackerel
• Scomberomorus concolor - Monterrey Spanish Mackerel
• Scomberomorus guttatus - Indo-Pacific King Mackerel
• Scomberomorus koreanus - Korean seerfish
• Scomberomorus lineolatus - Streaked Seerfish
• Scomberomorus maculatus - Atlantic Spanish Mackerel
• Scomberomorus munroi - Australian spotted mackerel
• Scomberomorus niphonius - Japanese Spanish mackerel
• Scomberomorus plurilineatus - Kanadi kingfish
• Scomberomorus queenslandicus - Queensland school mackerel
• Scomberomorus regalis - Cero mackerel
• Scomberomorus semifasciatus - Broadbarred king mackerel
• Scomberomorus sierra - Pacific sierra
• Scomberomorus sinensis - Chinese seerfish
• Scomberomorus tritor - West African Spanish mackerel
• Thunnus alalunga - Albacore
• Thunnus albacares - Yellowfin tuna
• Thunnus maccoyii - Southern bluefin tuna
• Thunnus obesus - Bigeye tuna
• Thunnus orientalis - Pacific bluefin tuna
• Thunnus thynnus - Northern bluefin tuna
• Thunnus tonggol - Longtail tuna 

Scombrid Video

The following is an account from National Geographic of a tuna fishing tradition in the Mediterranean.