Author: Alex Tyrrell
Alex is a professional underwater photographer ，based in Thailand，running Dive4Photos，a dedicated underwater photography training facility on Koh Tao，He writes regular articles and provides images for numerous dive magazines，presents at dive shows，and has been one of the judges of the Underwater Macro Photographers Group monthly photo competition from its outset in 2014. He was also a judge for the Asia Pacific UW Photo Challenge in 2017 and will be again in 2018.
Alex started diving in 2001 back in the UK ，and took up underwater photography in 2-years later，, becoming more serious in 2006 when he purchased his first DSLR set-up，Ever since he has been working in the dive industry at various locations around Asia，as a dive instructor, dive guide and photo pro/photo instructor，logging more than 4500 dives to date.
Working in the dive industry means I get to dive very regularly，allowing me to witness the breeding cycles of marine creatures on my local dive sites throughout the month，This lets me plan my photo dives to coincide for when they have eggs, or if I have found a creature with eggs whilst guiding, return later with my camera，Researching your potential subjects spawning habits combined with some careful planning will greatly improve your chances of capturing shots of eggs，in the marine environment.
The majority of fish species reproduce in a method known as broadcast spawning，or pelagic spawning，meaning that they release free floating gametes (sperm and eggs) into the water column，that drift away in the current，This normally involves a male and female of a particular species, but can sometimes involve aggregations of fish，participating in a ‘spawning rise’ ，that are typically very quick ，and culminate in the gamete release at its peak，This usually occurs at either dawn ，or dusk，This behaviour is not therefore so regularly photographed，with an exception of Mandarinfish，in the tropical Indo-Pacific region，.
In many circumstances timing is crucial，to catch your subject with eggs，meaning you need to know the tidal cycle phase，so you can coincide your dive for when the creatures have produced eggs，It is therefore important to know your subjects mating habits, as if you time it wrong, there will not be any eggs for you to shoot!
For those not familiar with moon phases, the different stages of the cycle are as follows:
– New (also called the Dark Moon)- not visible
– Waxing Crescent
– First Quarter - commonly called a "half moon"
– Waxing Gibbous - More than half of the Moon
– Full - we can see the entire illuminated portion of the moon
– Waning Gibbous
– Third Quarter - another "half moon"，but opposite of the First Quarter
– Waning Crescent
Normally eggs will hatch，when there are stronger currents to disperse the larvae,，so around the times of the full and new moon. Knowing the moon phase allows you to coincide your dives for when eggs are at an advanced stage of development..
Lens selection will vary dependent on the subject’s size and behaviour. A macro set-up is generally best for capturing images of marine creatures eggs.
A 60mm macro lens will work，60but the subject needs to be very close to the front of the port to obtain the required magnification，and this can scare off certain subjects，So a focal length of 105mm or longer，that enables a 1:1 reproduction ratio，with a greater working distance，is preferable in most situation，This is especially true ，105if you are shooting with an FX Sensor，60On Mirrorless Systems that have a 2x Crop Factor the 60mm is the best lens choice，45mm is an alternative.
For some shots，you will want increased levels of magnification，in order to record the detail of the eggs，The most common way of achieving this is to use a close-up lens or diopter
These reduce the minimum focusing distance of the lens，enabling you to get closer to your subject，creating greater magnification，So it's best to add a rollover adapter，But they also restrict the maximum focusing distance so mounting on a flip-adapter is the best option for speedy deployment/removal underwater
They come in various strengths from +5 through to +25，though be aware the greater the level of magnification，the shorter the working distance，so you need to take into account how close you can get to the subject，Depth of Field will also be reduced，and again the stronger the wet-lens the more the reduction ，so to maintain DOF small apertures are needed - I regularly use f32 or f36 with the Nauticam SMC.
This set-up works for eggs that are on the substrate，like Anemonefish，and some Crustaceans that are not too bothered about close proximity，But for shy subjects you cannot normally approach to within the working distance，unless you go for a lower magnification..
Common alternatives to gain additional magnification are either a close-up filter that attach to the front of your lens or a Teleconvertor，which fits in between the camera body and lens，Both of these go inside the housing，so you are locked-in to the set-up for the entire dive, making the more versatile wet-lens the common weapon of choice，The close-up filter works in exactly the same way as a macro wet-lens，Teleconverters come in different magnification strengths, the most popular being 1.4 and 2x, which simply magnifying your lens by ratio，but still retain the same minimum focusing distance for shy subjects.
Straightforward front lighting works well for most egg shots，A single strobe is sufficient，however when shooting at smaller apertures the additional light from a second strobe is beneficial，as is when shooting from distance.
The following potential subjects are from the Indo-Pacific region.，You needs some reserch of the local marine creatures in order to understand the creatures you might encounter.
Probably the most commonly photographed species of spawning fish，as they are found in the same area day after day and mate most evenings at sunset，Mating period was also fastened to the sunset time. The best moment is the mating time.，.
set continuous shooting mode，increase ISO, dial-down strobe power for quick recycling ，& shoot off a burst of frames to capture the action，If there is a current present，have it to your back，as the fish will face into it and you don’t then get a butt-shot
They lay their eggs right next to their host Anemone，so are one of the easiest fish eggs to shoot，I have found this to occur on the Waxing Gibbous and they develop ready to hatch around the Full Moon.
shoot close-ups of the developed eggs，showing the embryos inside，Also back off for a behaviour shot of the adults caring for the eggs，as they blow oxygenated water over them and clear algae build-up with their fins
These are mouth brooders，where the males incubate the fertilized eggs inside their mouth to protect them，from being eaten by other fish，The eggs develop through the Waxing Crescent to around Full Moon，Look for individuals with extended lower jaw cavities, as these are the males with eggs
Use a longer lens to give them room，or they will continually turn away from you，The moment to shoot is when they spit them out and rotate them (know as churning) that ensure equal development of the eggs，But be quick，as it only takes them a second or so to do this.
Many species carry the eggs，on the underside of their abdomen，Some shrimp will carry their eggs internally，and these can be seen with more transparent species，.
a longer lens is normally the best option to give you working room ，so you don’t spook the subject，Combine this with a wet lens for smaller subjects ，and you will be able to cover the majority of crustaceans
There are various other marine creatures whose eggs can make interesting subjects，Nudibranchs can regularly be seen laying egg-ribbons，some Frogfish species carry eggs on their side, Coral Gobies attach eggs to their host coral and Slippery Gobies lay eggs inside discarded bottles，jars and coconut shells，In the critter diving destinations of Asia you can find flamboyant cuttlefish laying eggs in cracks and crevices，and if you’re very lucky, you may find the coveted Blue-Ringed Octopus carrying a clutch of with eggs.
So to summarize，get to know your subject and it’s spawning cycle，get to know your subject and it’s spawning cycle，select the most suitable camera set-up and be patient when you find a good subject to maximize your chances of capturing an ‘egg-cellent shot’.