Mulies & Scalies – Some Facts

I read with interest the recent post by Black Gen regarding his inability to find good quality mulies that do not deteriorate when defrosted.  I also noted the thread comments, and thanks to those that mentioned the quality of Shore Catch products. 

I am not a fisheries expert however thought I would set out some relevant considerations when purchasing mulies and scalies.  Over the past few years we have sold 18 tonnes of mulies (WA Pilchards – Sardinops sagax) as retail products.  In comparison, over the same period, we have sold 4 tonnes of scalies (Tropical Sardines, Scaly Mackerel - Sardinella lemuru) so that gives some idea of general preference in the recreational fishing community. 

If you are interested about the biology and other factors regarding these species, the WA Department of Primary Industries and Regional Development has published a report for the federal government titled West Coast Purse Seine Managed Fishery and Development Zones (2019) which can be found at:  In general, mulies and scalies are small pelagic bait fish that are purse seine netted in schools by a limited number of commercial fishermen.  The fishery is currently recovering and the raw products are of a very high quality, being exported throughout Australia.

“Fish is very perishable due to the presence of high moisture, protein and highly oxidizable poly-unsaturated fatty acids, making it vulnerable to various biochemical, physical and microbial forms of deterioration throughout the production chain.”  I was doing some research about this matter and came across a scientific paper, where the above quote came from, that set out the various processes regarding fish spoilage and I have included a link to that text below for those that are interested.,Spoilage%20of%20fish,for%20prolonged%20period%20various%20preservation%20methods%20are%20being%20employed%20worldwide.,-Fish%20preservation

The key issue regarding the quality of the product is that fish rapidly deteriorate once caught (this was once a significant constraint to the mulies and scalies industry) therefore the post capture handling proceedures are critical.  Fresh fish must be stored at close to zero degrees from the time of capture until sale to ensure optimum possible quality.  Freezing is a preservation method, amongst others, but cannot reverse the degradation that has already occurred.  Importantly, storage temperature when frozen must be maintained at minus 18 or lower and if the products are partially thawed and refrozen then rapid degradation can occur through that process.  Mulies and scalies are small fish, so in general degrade more rapidly than larger fish (shelf life at zero degrees is really only a few days at most).  Note that fish also have limited freezer shelf life and are subject to dehydration over time (freezer burn), with smaller fish likely to “burn” in a shorter time frame.

There is no doubt that individually quick frozen (IQF) fish are better quality than those that are frozen in block form as the freezing process is much faster and the fish has less time to degrade.  In general, blocks take time to freeze and the small baitfish can lose moisture before becoming frozen resulting in the fish being preserved in liquid waste products.  This inferior technique inevitably leads to a high potential of the fish becoming “mushy” once the block and associated liquid defrost.

Given the above, the following questions are relevant when looking for the best quality mulies and scalies.

  1. Was the fish immediately chilled on capture, and was near zero temperature maintained when fresh?  Generally speaking, all licenced fishermen will appropriately chill the fish on capture so this is not really a determining factor.
  2. Is the frozen fish in IQF or block form?  As noted, IQF fish are generally of a better quality although if the individual fish is allowed to partially thaw during the secondary packing process then quality is diminished.
  3. How long has the fish been frozen?  This information is not readily available so it takes a keen eye to determine the extent of freezer burn.  Sometimes retailers will heavily discount “old” fish in order to gain some return for a substandard product.
  4. Has the fish always been frozen stored at or below minus 18 degrees?  Again, this takes an experienced eye to determine degradation level prior to purchase but is easy to know once the fish is defrosted.  The common cause for poor quality by partial defrosting is a freezer being left open or failing, and then the products are refrozen when they should be discarded.

With all of this in mind, the best mulies and scalies will be purchased from a business that looks after its products at all times and has a high throughput so that freezer time in secondary packaging is minimised.  Your local reputable tackle shop will, in all probability, have higher throughput and staff that are vigilant in relation to the freezers so is clearly a better option than service stations or low bait volume stores. 

The bait industry currently has no obligation to show capture date or best before date therefore the consumer is at a general disadvantage in assessing quality at retail purchase.  It is however bait, which if frozen and stored appropriately should have a shelf life between 6 and 12 months.

Anyway, for those that have read this far I hope you found the information interesting.



Ability is what you are capable of doing. Motivation determines what you do. Attitude determines how well you do it - LH.


sea-kem's picture

Posts: 13492

Date Joined: 30/11/09

 Thanks for taking the time

Wed, 2021-08-25 06:22

 Thanks for taking the time to put that up Mick, some good info there. Interesting that there's no date coding, I guess to minimise wastage as punters won't buy older stock and would just end up being thrown out or made into a cheaper selling burley. 

Whenever I buy Mulies or Scalies always have a rummage through to check quality and baitfish sizing to suit rig style and  what I'm chasing. 


Love the West!

black gen's picture

Posts: 730

Date Joined: 13/04/11

 Good onya mick that's a

Wed, 2021-08-25 19:22

 Good onya mick 

that's a great write up and some interesting points raised there too 

for the record the scalies left the mulies for dead in coral bay in all areas

staying on the hook, not breaking down so fast as the day went on 

refeeezing and defrosting some of them even then the scalies were still usable 


think I've used my last mulie

Brock O's picture

Posts: 2662

Date Joined: 11/01/08

Onya Mick, getting table fish

Thu, 2021-08-26 07:40

Onya Mick, getting table fish spiked and on a ice slurry is always a priority on my boat.

As above when snapper fishing I only buy the 2kg mulie blocks for burley, 1kg bags of scalies for hook bait as there hardier and last longer compared to a mulie. I think a lot of fisho's starting out may go straight to the mulies.

Always got the small rod out catching herring and yellow tail for bait when possible.

davewillo's picture

Posts: 973

Date Joined: 08/09/16

 Thanks for taking the time

Thu, 2021-08-26 11:04

 Thanks for taking the time Mick. If I use mulies I always buy IQF for the above reasons. It's more expensive obviously but way better and easier to check the quality visually too.

duncan61's picture

Posts: 350

Date Joined: 21/11/14

preston beach

Thu, 2021-08-26 17:48

 When I lived at Preston beach I was often given large numbers of thawed out mulies and I would salt them in batches of a dozen to a sheet of newspaper.I would sprinkle a small amount on both sides if I used to much they would go hard 2 soon.The fridge life was about a month and I would take 24-36 mulies for a beach session.It took 48 hours for them to toughen up but still be useable.Caught plenty of tailor


just do it.