Measuring Fish Length

Measuring Fish Length

Lengths should be recorded on all claims submitted. Lengths (cm) as submitted on each claim form were presented in the 2010 report for the first time in 2009. Lengths (cm) should be recorded on ALL claims submitted. All fish must be placed on measuring device & measured from tip of nose to end of middle rays of tail fin (forklength) OR for marine species (except blue shark) to end of tail fin. Greatest girth – in front of dorsal fin. Wingspread (rays and skate) from wingtip to wingtip. Photos supporting length specified should accompany claim, showing fish belly down ON measuring device showing actual fish length (cm) – tip of snout (placed against bar) to end of tail fin lobe.

Significant length variation is evident for most species. This is due to natural variability (time of year, sex, location, feeding etc) but it is likely that fish length measurement techniques were inconsistent also.

Inland Fisheries Ireland sells measuring mats online at cost (€19.99) plus postage (€9.00) for a total of €28.99. Two versions are available a 170cm mat ideal for pike, tope, smoothhound and spurdog anglers (and all the other fish unlikely to exceed 170cm) and a 230cm version ideal for sharks and skate.

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The ISFC requests that all specimen fish are measured according to table below

Measurement (cm) required
ALL Marine species
(except blue sharks and porbeagle sharks)
Total lengthPlace fish on top of measuring device and measure in an straight line from tip of snout to end of tail
ALL Marine species
(except ray and skate)
GirthMeasure greatest girth using tape measure - usually in front of dorsal fin
Ray and skateWingspanPlace fish on top of measuring device and measure from wingtip to windtip
ALL Freshwater speciesForklengthPlace fish on top of measuring device and measure from tip of snout to middle rays of tail
ALL Sharks, Rays and SkatesSex - state on claim form if fish is male or femaleMales can be identifies by their claspers (modified pelvic fins) which are thin elongated paired fins situated behind the pelvic fins. Females do not have claspers but have an opening between the pelvic fins.