Full Description

"The streaked gurnard Trigloporus lastoviza produced only one sound type, a growl, lasting up to 3 s and consisting of repeated groups of typically one to three pulses."

"In the first, the fish circled the feeding area, grasped a food item and fled, sometimes displaying aggressively to competitors. With this foraging strategy, fish usually made sounds as they circled, grasped and fled. Fish that growled while circling were more likely to grasp a food item subsequently than were silent fish. The second feeding strategy occurred when a fish had already ingested food or failed to get any. In this case, typically fish searched for food on the substratum or approached and touched other individuals that were feeding, sometimes grabbing food that was spat out during food handling by the other fish. Although payback experiments would be needed to draw firm conclusions on the communicative function of growling during competitive feeding in the streaked gurnard, the results suggest that sound production confers advantages to individuals competing for limited food resources."

"The acoustic signals made by triglids, including those of the streaked gurnards, are loud and conspicuous with main frequencies falling within the typical hearing sensitivity of fishes (Hawkins, 1993; Amorim, 1996)."

"Example of a growl produced by the streaked gurnard. (a) Sonogram and oscillogram of a section of the growl sound (filter bandwidth=125 Hz). Note that the sound pulses are organized in groups; this section shows six groups each consisting of one, two or three pulses. (b) Envelope of the whole growl."

"The studied streaked gurnards emitted only one sound type, a growl. Growls were low frequency sounds composed of pulses. The pulses within a single growl were organized in groups of typically one to three pulses (Fig. 1). A group of pulses within a growl was identified easily in the oscillogram since the interval between groups was significantly longer than the interval between pulses within a group (Fig. 1; Table I)."

"Also growls were heard, less frequently, from fish that were not interacting with conspecifics. Sound emissions and associated behavioural acts that occurred during video feeding sessions but outside feeding interactions were registered also. In addition, because the behaviour grasp was clearly associated with sound production, all occurrences of this behaviour outside feeding interactions were recorded, registering also whether each occurrence was accompanied by sound."

"The only sound type produced by streaked gurnards was a long growl, that could last for up to 3 s (Table I). These sound emissions were composed of short sound pulses, c. 5 ms long (Fig. 1; Table I). On average, a growl was made of 37 groups of pulses each consisting typically of 1–3 pulses (Table I). Pulse and group period averaged c. 4 and 23 ms, respectively (Table I). Typical peak frequencies of growls lay between 400–600 Hz."

"Almost half (mean=46·4%, S.D.=16·3, min=25·9%, max=18·6%, n=194) of the total number of interactions observed in eight recording sessions were accompanied by sound production."

"Behavioural acts and sound production occurring during competitive feeding interactions were significantly dependent ( x^2=612·85, n=1901, d.f.=10, P<0·001). Sound production was associated mainly with the behavioural acts grasp (P<0·001), circle (P<0·001), and flee (P<0·05, programme ACTUS) (Fig. 4)."

"Outside fish feeding interactions only 36 growls were heard (16·7% of the total), of which 29 accompanied the behaviour grasp, three circle, two feed, one flee and one swim. The behaviour grasp occurred 39 times outside interactions (18·4%), of which 29 (74·4%) were accompanied by sound emissions. Overall, 62·7% of grasps (occurring during or outside interactions) were accompanied by sound emission. Grasp seems to be the most important behavioural category related to growl emission during feeding interactions as well as outside them. The number of growls in an interaction were not correlated significantly with the number of fish involved in the interaction (Spearman correlation: n=465, P>0·05). Circles accompanied by growls were more likely to be followed by grasps (Wilcoxon test: n=8, Z= - 2·401, P<0·05) than by other behavioural acts, and silent circles were more likely to be followed by other behavioural acts (Wilcoxon test: n=8, Z= - 2·401, P<0·05)."

"Streaked gurnards growled frequently while competing for food."

"Growling may reflect a state of feeding arousal caused by the sight of food or be associated with low levels of aggression."

Observation Environment Quotes

"Here, the significance of sound production in the streaked gurnard has been studied during competitive feeding in captivity."

"Streaked gurnards were captured by trawling in the Eastern Mediterranean, off the Bay of Iraklion (Crete, Greece), at depths of 10–15 m. Trawl duration was short to minimize skin and fin damage and shallow trawling depths aimed to avoid swimbladder damage. Fish were kept in 1800-l fibreglass tanks at the Institute of Marine Biology of Crete, Iraklion, provided with aeration and filtered recirculated sea water."

Behaviour Description Quotes

"Although payback experiments would be needed to draw firm conclusions on the communicative function of growling during competitive feeding in the streaked gurnard, the results suggest that sound production confers advantages to individuals competing for limited food resources."

"Behavioural acts and sound production occurring during competitive feeding interactions were significantly dependent ( x^2=612·85, n=1901, d.f.=10, P<0·001). Sound production was associated mainly with the behavioural acts grasp (P<0·001), circle (P<0·001), and flee (P<0·05, programme ACTUS) (Fig. 4)."

"Streaked gurnards growled frequently while competing for food."

"Growling may reflect a state of feeding arousal caused by the sight of food or be associated with low levels of aggression."

Sound Name Quotes

"The streaked gurnard Trigloporus lastoviza produced only one sound type, a growl, lasting up to 3 s and consisting of repeated groups of typically one to three pulses."

" Streaked gurnards have a large physoclist swimbladder (Davenport, 1999), with a pair of strongly developed intrinsic sonic muscles, embedded laterally on either side. Rapid contractions of the sonic muscles cause the swimbladder wall to vibrate rhythmically, producing a typical drumming sound (Hawkins, 1968; Amorim, 1996)."