Yellowtail Scad - Trachurus novaezelandiae

Large schools of Yellowtail Scad (Trachurus novaezelandiae) are a common sight around Terrigal, especially just past the anchor in the Haven. These common fish are also known as Yakkas (by fishermen), Yellowtails or Horse mackerel. The photo below shows their usual schooling behaviour, with some near-shore schools containing hundreds (even thousands in the bigger schools) of individuals.

Schooling Yellowtail Scad above a kelp covered rock in Terrigal Haven. Photo by Dave Jones

Yellowtail Scad seem to be drawn to pylons and other structures and are generally seen schooling around natural outcrops, such as raised macroalgae covered boulders. They feed on zooplankton and make erratic darting movements out from the edge of the school mass then quickly retreat back into the centre when they are feeding.

This fish is easy to identify due to the schooling behaviour and distinct silver body with bright yellow forked tail. They commonly grow to around 30cm although individuals reaching up to 50cm have been recorded.

The Yellowtail Scad is commonly caught and used as live bait by rock fisherman in their attempts to catch large tuna and kingfish.

Close up of a Yellowtail Scad school. Photo by Keith Bishop

 

Hundreds of Yellowtail Scad schooling above macroalgae at Terrigal. Photo by Keith Bishop

They are regarded as a poor eating fish by seafood eaters. However, divers love seeing schools of Yellowtail Scad. If you are patient and calm enough the school will acclimatise to your presence and eventually encircle you. It's an awesome feeling! Keep an eye out when you see Yellowtail Scad as you may see large kingfish rounding up the school. Yellowtail Scad are one of the kingfishes main source of food.

Sergeant Baker - Hime purpurissatus

The Sergeant Baker (Hime purpurissatus) is a common fish often seen resting on rocks at the Haven and many other places around the Central Coast.

Sergeant Baker - Commonly seen resting on rocks. Photo by Keith Bishop.

 

It's easy to tell the difference between males and females by looking at their dorsal fin (the fins/rays on their back just behind their head). Males have an elongated ray that can almost reach the tail in some older individuals. Females lack this elongated fin ray.

Female Sergeant Baker. Photo by Keith Bishop.

Male Sergeant Baker. Photo by Keith Bishop.

Sergeant Bakers can grow to around 70cm in length and are found all around the bottom of Australia from central WA to southern QLD. Unfortunately for all you seafood eaters, this fish is reported to have poor tasting flesh.

Male Sergeant Baker displaying extended dorsal fin ray.

Sergeant Bakers are not an aggressive fish and are easy to approach when they are resting on the bottom. You can tell when you have pushed your limits and the fish is getting annoyed as they will raise their dorsal fin and usually just quickly jump up and swim away.

 

I have found the best way to approach if you want a closer look or to get some good photos (like Keith has above), is to stay low and creep up slowly. Once the dorsal fin starts to raise you know you have reached the point where the fish starts to feel threatened. Back away slightly and the fin should go down, then slowly start to move forward again. This way the fish gets acclimatised to you a bit better and seems to feel more comfortable.

 

As always with marine life - Do not purposely stir up or harass these fish (or any marine creature). Enjoy looking at these awesome fish and enjoy your diving!

Magnificent Ascidian - Botrylloides magnicoecum

I'll start this blog with a marine creature I used to look at regularly, but had no idea what I was actually looking at! Below are two photos of a Magnificent Ascidian (Botrylloides magnicoecum) taken on the Central Coast, NSW. This species of ascidian is very common around Australia and can be found in many other parts of the world.

Magnificent Ascidian - Botrylloides magnicoecum

Magnificent Ascidian - Botrylloides magnicoecum

  

The Magnificent Ascidian is a colonial species, meaning that many individual organisms make up the large community. Individual zooids attach to the larger thumb shaped lobe which form the blue patterns. These small (1-2mm) zooids intake water filled with nutrients which nourish the colony. The large communal siphon at the top of each lobe is used to siphon the used water out of the colony.

Davey Jones' Locker

Hello good people of the scuba diving community!

I have started this blog to provide some basic, yet interesting, information on species found in our local area - Central Coast of New South Wales.

First, let me start by saying that I am by no means an expert on marine life. I am currently in my third year of studying Marine Science at the University of Newcastle. I have an affinity for all forms of life, but I particularly love marine life. So this blog is my attempt to educate local divers on local species. I'm aiming at providing enough information so you can learn something about the creatures commonly seen on local dives (and so you can pull out some cool marine facts around the dinner table).

Let me know via email, comments or in person if there is a local species that you seen often, but never know much about and I'll do my best to get some great information for you.

Keep blowing bubbles,
Dave

This is me. Posing. Stunning.
Ladies, get in line.